diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
index caf0e06379e..270e5a2b6d9 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
@@ -48,6 +48,7 @@
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryMode;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryOptions;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.ReadRequest;
 import com.google.spanner.v1.RequestOptions;
@@ -878,10 +879,19 @@ String getTransactionTag() {
     return null;
   }
 
+  @Nullable
+  MultiplexedSessionPrecommitToken getLatestPrecommitToken() {
+    return null;
+  }
+
   /** This method is called when a statement returned a new transaction as part of its results. */
   @Override
   public void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId) {}
 
+  /** This method is called when a response returns a new pre-commit token as part of its results. */
+  @Override
+  public void onPrecommitToken(MultiplexedSessionPrecommitToken token){}
+
   @Override
   public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
     this.session.onError(e);
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
index 2cf93fb92ec..47067b0c0b4 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
@@ -27,6 +27,7 @@
 import com.google.protobuf.ListValue;
 import com.google.protobuf.ProtocolMessageEnum;
 import com.google.protobuf.Value.KindCase;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.Transaction;
 import java.io.IOException;
 import java.io.Serializable;
@@ -52,6 +53,8 @@ interface Listener {
     void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId)
         throws SpannerException;
 
+    void onPrecommitToken(MultiplexedSessionPrecommitToken token);
+
     /** Called when the read finishes with an error. Returns the error that should be thrown. */
     SpannerException onError(SpannerException e, boolean withBeginTransaction);
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java
index 909d731818f..f0ceb72eea2 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java
@@ -241,7 +241,7 @@ public ReadOnlyTransaction readOnlyTransaction(TimestampBound bound) {
   public TransactionRunner readWriteTransaction(TransactionOption... options) {
     ISpan span = tracer.spanBuilder(READ_WRITE_TRANSACTION, options);
     try (IScope s = tracer.withSpan(span)) {
-      return getSession().readWriteTransaction(options);
+      return getMultiplexedSession().readWriteTransaction(options);
     } catch (RuntimeException e) {
       span.setStatus(e);
       span.end();
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcResultSet.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcResultSet.java
index be75c1e5c4e..23c9dd7c2d3 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcResultSet.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcResultSet.java
@@ -47,7 +47,7 @@ class GrpcResultSet extends AbstractResultSet<List<Object>> implements ProtobufR
 
   GrpcResultSet(
       CloseableIterator<PartialResultSet> iterator, Listener listener, DecodeMode decodeMode) {
-    this.iterator = new GrpcValueIterator(iterator);
+    this.iterator = new GrpcValueIterator(iterator, listener);
     this.listener = listener;
     this.decodeMode = decodeMode;
   }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcValueIterator.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcValueIterator.java
index 0a2e17bd2b5..b78a1e1d73f 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcValueIterator.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/GrpcValueIterator.java
@@ -20,9 +20,11 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.cloud.spanner.AbstractResultSet.CloseableIterator;
+import com.google.cloud.spanner.AbstractResultSet.Listener;
 import com.google.common.collect.AbstractIterator;
 import com.google.protobuf.ListValue;
 import com.google.protobuf.Value.KindCase;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.ResultSetMetadata;
 import com.google.spanner.v1.ResultSetStats;
@@ -44,9 +46,12 @@ private enum StreamValue {
   private PartialResultSet current;
   private int pos;
   private ResultSetStats statistics;
+  private MultiplexedSessionPrecommitToken precommitToken;
+  private final Listener listener;
 
-  GrpcValueIterator(CloseableIterator<PartialResultSet> stream) {
+  GrpcValueIterator(CloseableIterator<PartialResultSet> stream, Listener listener) {
     this.stream = stream;
+    this.listener = listener;
   }
 
   @SuppressWarnings("unchecked")
@@ -154,6 +159,10 @@ private boolean ensureReady(StreamValue requiredValue) throws SpannerException {
               ErrorCode.INTERNAL, "Invalid type metadata: " + e.getMessage(), e);
         }
       }
+      // Collect precommit token from all PartialResultSet
+      if(current.hasPrecommitToken()) {
+        listener.onPrecommitToken(current.getPrecommitToken());
+      }
       if (current.hasStats()) {
         statistics = current.getStats();
       }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java
index 81415e80d25..08f96b6e021 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java
@@ -404,6 +404,11 @@ public ReadOnlyTransaction readOnlyTransaction(TimestampBound bound) {
     return createMultiplexedSessionTransaction(false).readOnlyTransaction(bound);
   }
 
+  @Override
+  public TransactionRunner readWriteTransaction(TransactionOption... options) {
+    return createMultiplexedSessionTransaction(false).readWriteTransaction(options);
+  }
+
   /**
    * It is enough with one executor to maintain the multiplexed sessions in all the clients, as they
    * do not need to be updated often, and the maintenance task is light. The core pool size is set
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
index 7b9abc71a85..4d6acba96a7 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
@@ -426,15 +426,18 @@ public void close() {
     }
   }
 
-  ApiFuture<ByteString> beginTransactionAsync(
-      Options transactionOptions, boolean routeToLeader, Map<SpannerRpc.Option, ?> channelHint) {
-    final SettableApiFuture<ByteString> res = SettableApiFuture.create();
+  ApiFuture<Transaction> beginTransactionAsync(
+      Options transactionOptions, boolean routeToLeader, Map<SpannerRpc.Option, ?> channelHint, com.google.spanner.v1.Mutation mutation) {
+    final SettableApiFuture<Transaction> res = SettableApiFuture.create();
     final ISpan span = tracer.spanBuilder(SpannerImpl.BEGIN_TRANSACTION);
-    final BeginTransactionRequest request =
+    BeginTransactionRequest request =
         BeginTransactionRequest.newBuilder()
             .setSession(getName())
             .setOptions(createReadWriteTransactionOptions(transactionOptions))
             .build();
+    if (sessionReference.getIsMultiplexed()) {
+      request = request.toBuilder().setMutationKey(mutation).build();
+    }
     final ApiFuture<Transaction> requestFuture;
     try (IScope ignore = tracer.withSpan(span)) {
       requestFuture = spanner.getRpc().beginTransactionAsync(request, channelHint, routeToLeader);
@@ -448,7 +451,7 @@ ApiFuture<ByteString> beginTransactionAsync(
                   ErrorCode.INTERNAL, "Missing id in transaction\n" + getName());
             }
             span.end();
-            res.set(txn.getId());
+            res.set(txn);
           } catch (ExecutionException e) {
             span.setStatus(e);
             span.end();
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionRunnerImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionRunnerImpl.java
index c8bf6dc833b..f3ec6013142 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionRunnerImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionRunnerImpl.java
@@ -46,6 +46,7 @@
 import com.google.spanner.v1.ExecuteBatchDmlResponse;
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryMode;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.RequestOptions;
 import com.google.spanner.v1.ResultSet;
 import com.google.spanner.v1.ResultSetStats;
@@ -171,6 +172,11 @@ public void removeListener(Runnable listener) {
     @GuardedBy("committingLock")
     private volatile boolean committing;
 
+    private final Object preCommitTokenLock = new Object();
+
+    @GuardedBy("preCommitTokenLock")
+    private MultiplexedSessionPrecommitToken latestPreCommitToken;
+
     @GuardedBy("lock")
     private volatile SettableApiFuture<Void> finishedAsyncOperations = SettableApiFuture.create();
 
@@ -268,7 +274,7 @@ void ensureTxn() {
     ApiFuture<Void> ensureTxnAsync() {
       final SettableApiFuture<Void> res = SettableApiFuture.create();
       if (transactionId == null || isAborted()) {
-        createTxnAsync(res);
+        createTxnAsync(res, null);
       } else {
         span.addAnnotation("Transaction Initialized", "Id", transactionId.toStringUtf8());
         txnLogger.log(
@@ -280,19 +286,23 @@ ApiFuture<Void> ensureTxnAsync() {
       return res;
     }
 
-    private void createTxnAsync(final SettableApiFuture<Void> res) {
+    private void createTxnAsync(final SettableApiFuture<Void> res, com.google.spanner.v1.Mutation mutation) {
       span.addAnnotation("Creating Transaction");
-      final ApiFuture<ByteString> fut =
-          session.beginTransactionAsync(options, isRouteToLeader(), getTransactionChannelHint());
+      final ApiFuture<Transaction> fut =
+          session.beginTransactionAsync(options, isRouteToLeader(), getTransactionChannelHint(), mutation);
       fut.addListener(
           () -> {
             try {
-              transactionId = fut.get();
+              Transaction txn = fut.get();
+              transactionId = txn.getId();
               span.addAnnotation("Transaction Creation Done", "Id", transactionId.toStringUtf8());
               txnLogger.log(
                   Level.FINER,
                   "Started transaction {0}",
                   txnLogger.isLoggable(Level.FINER) ? transactionId.asReadOnlyByteBuffer() : null);
+              if (txn.hasPrecommitToken()) {
+                onPrecommitToken(txn.getPrecommitToken());
+              }
               res.set(null);
             } catch (ExecutionException e) {
               span.addAnnotation(
@@ -370,7 +380,7 @@ ApiFuture<CommitResponse> commitAsync() {
       synchronized (lock) {
         if (transactionIdFuture == null && transactionId == null && runningAsyncOperations == 0) {
           finishOps = SettableApiFuture.create();
-          createTxnAsync(finishOps);
+          createTxnAsync(finishOps, mutationsProto.get(0));
         } else {
           finishOps = finishedAsyncOperations;
         }
@@ -423,6 +433,13 @@ public void run() {
             }
             requestBuilder.setRequestOptions(requestOptionsBuilder.build());
           }
+          if (session.getIsMultiplexed()) {
+            requestBuilder.setPrecommitToken(getLatestPrecommitToken());
+            System.out.println("setting precommit token in request");
+            System.out.println(requestBuilder.getPrecommitToken().getPrecommitToken());
+
+            txnLogger.log(Level.ALL, "setting  precommit token to commit "+requestBuilder.getPrecommitToken().getPrecommitToken());
+          }
           final CommitRequest commitRequest = requestBuilder.build();
           span.addAnnotation("Starting Commit");
           final ApiFuture<com.google.spanner.v1.CommitResponse> commitFuture;
@@ -625,6 +642,17 @@ public void onTransactionMetadata(Transaction transaction, boolean shouldInclude
       }
     }
 
+    public void onPrecommitToken(MultiplexedSessionPrecommitToken token){
+      if(token == null) return;
+      synchronized (preCommitTokenLock) {
+        if (this.latestPreCommitToken == null || token.getSeqNum() > this.latestPreCommitToken.getSeqNum()) {
+          this.latestPreCommitToken = token;
+          System.out.println("Updating precommit token to "+this.latestPreCommitToken);
+          txnLogger.log(Level.ALL, "Updating precommit token to "+this.latestPreCommitToken);
+        }
+      }
+    }
+
     @Nullable
     String getTransactionTag() {
       if (this.options.hasTag()) {
@@ -633,6 +661,13 @@ String getTransactionTag() {
       return null;
     }
 
+    @Nullable
+    MultiplexedSessionPrecommitToken getLatestPrecommitToken() {
+      synchronized (preCommitTokenLock) {
+        return this.latestPreCommitToken;
+      }
+    }
+
     @Override
     public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
       e = super.onError(e, withBeginTransaction);
@@ -811,6 +846,9 @@ private ResultSet internalExecuteUpdate(
           throw new IllegalArgumentException(
               "DML response missing stats possibly due to non-DML statement as input");
         }
+        if (resultSet.hasPrecommitToken()) {
+          onPrecommitToken(resultSet.getPrecommitToken());
+        }
         return resultSet;
       } catch (Throwable t) {
         throw onError(
@@ -885,6 +923,9 @@ public ApiFuture<Long> executeUpdateAsync(Statement statement, UpdateOption... u
                       resultSet.get().getMetadata().getTransaction(),
                       builder.getTransaction().hasBegin());
                 }
+                if (resultSet.get().hasPrecommitToken()) {
+                  onPrecommitToken(resultSet.get().getPrecommitToken());
+                }
               } catch (Throwable e) {
                 // Ignore this error here as it is handled by the future that is returned by the
                 // executeUpdateAsync method.
@@ -938,6 +979,10 @@ public long[] batchUpdate(Iterable<Statement> statements, UpdateOption... update
                   response.getResultSets(i).getMetadata().getTransaction(),
                   builder.getTransaction().hasBegin());
             }
+            // TODO(harsha): check if we need to get precommit_token from response.getResultSets
+            if (response.hasPrecommitToken()) {
+              onPrecommitToken(response.getPrecommitToken());
+            }
           }
 
           // If one of the DML statements was aborted, we should throw an aborted exception.
@@ -1004,6 +1049,9 @@ public ApiFuture<long[]> batchUpdateAsync(
                           builder.getTransaction().hasBegin());
                     }
                   }
+                  if (batchDmlResponse.hasPrecommitToken()) {
+                    onPrecommitToken(batchDmlResponse.getPrecommitToken());
+                  }
                   // If one of the DML statements was aborted, we should throw an aborted exception.
                   // In all other cases, we should throw a BatchUpdateException.
                   if (batchDmlResponse.getStatus().getCode() == Code.ABORTED_VALUE) {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
index 64ffdb0902a..8625c17785a 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
@@ -1629,6 +1629,7 @@ public final Transaction beginTransaction(String session, TransactionOptions opt
    *               SessionName.of("[PROJECT]", "[INSTANCE]", "[DATABASE]", "[SESSION]").toString())
    *           .setOptions(TransactionOptions.newBuilder().build())
    *           .setRequestOptions(RequestOptions.newBuilder().build())
+   *           .setMutationKey(Mutation.newBuilder().build())
    *           .build();
    *   Transaction response = spannerClient.beginTransaction(request);
    * }
@@ -1662,6 +1663,7 @@ public final Transaction beginTransaction(BeginTransactionRequest request) {
    *               SessionName.of("[PROJECT]", "[INSTANCE]", "[DATABASE]", "[SESSION]").toString())
    *           .setOptions(TransactionOptions.newBuilder().build())
    *           .setRequestOptions(RequestOptions.newBuilder().build())
+   *           .setMutationKey(Mutation.newBuilder().build())
    *           .build();
    *   ApiFuture<Transaction> future = spannerClient.beginTransactionCallable().futureCall(request);
    *   // Do something.
@@ -1911,6 +1913,7 @@ public final CommitResponse commit(
    *           .setReturnCommitStats(true)
    *           .setMaxCommitDelay(Duration.newBuilder().build())
    *           .setRequestOptions(RequestOptions.newBuilder().build())
+   *           .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
    *           .build();
    *   CommitResponse response = spannerClient.commit(request);
    * }
@@ -1955,6 +1958,7 @@ public final CommitResponse commit(CommitRequest request) {
    *           .setReturnCommitStats(true)
    *           .setMaxCommitDelay(Duration.newBuilder().build())
    *           .setRequestOptions(RequestOptions.newBuilder().build())
+   *           .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
    *           .build();
    *   ApiFuture<CommitResponse> future = spannerClient.commitCallable().futureCall(request);
    *   // Do something.
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerSettings.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerSettings.java
index a785ff6d993..721e874e01e 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerSettings.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerSettings.java
@@ -76,7 +76,9 @@
  * <p>The builder of this class is recursive, so contained classes are themselves builders. When
  * build() is called, the tree of builders is called to create the complete settings object.
  *
- * <p>For example, to set the total timeout of createSession to 30 seconds:
+ * <p>For example, to set the
+ * [RetrySettings](https://cloud.google.com/java/docs/reference/gax/latest/com.google.api.gax.retrying.RetrySettings)
+ * of createSession:
  *
  * <pre>{@code
  * // This snippet has been automatically generated and should be regarded as a code template only.
@@ -92,10 +94,21 @@
  *             .createSessionSettings()
  *             .getRetrySettings()
  *             .toBuilder()
- *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .setInitialRetryDelayDuration(Duration.ofSeconds(1))
+ *             .setInitialRpcTimeoutDuration(Duration.ofSeconds(5))
+ *             .setMaxAttempts(5)
+ *             .setMaxRetryDelayDuration(Duration.ofSeconds(30))
+ *             .setMaxRpcTimeoutDuration(Duration.ofSeconds(60))
+ *             .setRetryDelayMultiplier(1.3)
+ *             .setRpcTimeoutMultiplier(1.5)
+ *             .setTotalTimeoutDuration(Duration.ofSeconds(300))
  *             .build());
  * SpannerSettings spannerSettings = spannerSettingsBuilder.build();
  * }</pre>
+ *
+ * Please refer to the [Client Side Retry
+ * Guide](https://github.com/googleapis/google-cloud-java/blob/main/docs/client_retries.md) for
+ * additional support in setting retries.
  */
 @Generated("by gapic-generator-java")
 public class SpannerSettings extends ClientSettings<SpannerSettings> {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/stub/SpannerStubSettings.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/stub/SpannerStubSettings.java
index fa6b86633b3..ae4b1c11daf 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/stub/SpannerStubSettings.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/stub/SpannerStubSettings.java
@@ -94,7 +94,9 @@
  * <p>The builder of this class is recursive, so contained classes are themselves builders. When
  * build() is called, the tree of builders is called to create the complete settings object.
  *
- * <p>For example, to set the total timeout of createSession to 30 seconds:
+ * <p>For example, to set the
+ * [RetrySettings](https://cloud.google.com/java/docs/reference/gax/latest/com.google.api.gax.retrying.RetrySettings)
+ * of createSession:
  *
  * <pre>{@code
  * // This snippet has been automatically generated and should be regarded as a code template only.
@@ -110,10 +112,21 @@
  *             .createSessionSettings()
  *             .getRetrySettings()
  *             .toBuilder()
- *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .setInitialRetryDelayDuration(Duration.ofSeconds(1))
+ *             .setInitialRpcTimeoutDuration(Duration.ofSeconds(5))
+ *             .setMaxAttempts(5)
+ *             .setMaxRetryDelayDuration(Duration.ofSeconds(30))
+ *             .setMaxRpcTimeoutDuration(Duration.ofSeconds(60))
+ *             .setRetryDelayMultiplier(1.3)
+ *             .setRpcTimeoutMultiplier(1.5)
+ *             .setTotalTimeoutDuration(Duration.ofSeconds(300))
  *             .build());
  * SpannerStubSettings spannerSettings = spannerSettingsBuilder.build();
  * }</pre>
+ *
+ * Please refer to the [Client Side Retry
+ * Guide](https://github.com/googleapis/google-cloud-java/blob/main/docs/client_retries.md) for
+ * additional support in setting retries.
  */
 @Generated("by gapic-generator-java")
 public class SpannerStubSettings extends StubSettings<SpannerStubSettings> {
@@ -177,9 +190,7 @@ public String extractNextToken(ListSessionsResponse payload) {
 
             @Override
             public Iterable<Session> extractResources(ListSessionsResponse payload) {
-              return payload.getSessionsList() == null
-                  ? ImmutableList.<Session>of()
-                  : payload.getSessionsList();
+              return payload.getSessionsList();
             }
           };
 
diff --git a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
index 4e56610da8f..ffa070f1225 100644
--- a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
+++ b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
@@ -305,6 +305,24 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.api.PythonSettings$ExperimentalFeatures",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
+  {
+    "name": "com.google.api.PythonSettings$ExperimentalFeatures$Builder",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.api.ResourceDescriptor",
     "queryAllDeclaredConstructors": true,
@@ -1727,6 +1745,24 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.spanner.v1.MultiplexedSessionPrecommitToken",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
+  {
+    "name": "com.google.spanner.v1.MultiplexedSessionPrecommitToken$Builder",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.spanner.v1.Mutation",
     "queryAllDeclaredConstructors": true,
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/CloseSpannerWithOpenResultSetTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/CloseSpannerWithOpenResultSetTest.java
index 67b14f60a4e..a489a269b22 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/CloseSpannerWithOpenResultSetTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/CloseSpannerWithOpenResultSetTest.java
@@ -39,6 +39,8 @@
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -59,6 +61,16 @@ Spanner createSpanner() {
         .getService();
   }
 
+  @BeforeClass
+  public static void setWatchdogTimeout() {
+    System.setProperty("com.google.cloud.spanner.watchdogTimeoutSeconds", "1");
+  }
+
+  @AfterClass
+  public static void clearWatchdogTimeout() {
+    System.clearProperty("com.google.cloud.spanner.watchdogTimeoutSeconds");
+  }
+
   @After
   public void cleanup() {
     mockSpanner.unfreeze();
@@ -75,7 +87,13 @@ public void testBatchClient_closedSpannerWithOpenResultSet_streamsAreCancelled()
             client.batchReadOnlyTransaction(TimestampBound.strong());
         ResultSet resultSet = transaction.executeQuery(SELECT_RANDOM_STATEMENT)) {
       mockSpanner.freezeAfterReturningNumRows(1);
-      assertTrue(resultSet.next());
+      // This can sometimes fail, as the mock server may not always actually return the first row.
+      try {
+        assertTrue(resultSet.next());
+      } catch (SpannerException exception) {
+        assertEquals(ErrorCode.DEADLINE_EXCEEDED, exception.getErrorCode());
+        return;
+      }
       ((SpannerImpl) spanner).close(1, TimeUnit.MILLISECONDS);
       // This should return an error as the stream is cancelled.
       SpannerException exception = assertThrows(SpannerException.class, resultSet::next);
@@ -93,7 +111,13 @@ public void testNormalDatabaseClient_closedSpannerWithOpenResultSet_sessionsAreD
     try (ReadOnlyTransaction transaction = client.readOnlyTransaction(TimestampBound.strong());
         ResultSet resultSet = transaction.executeQuery(SELECT_RANDOM_STATEMENT)) {
       mockSpanner.freezeAfterReturningNumRows(1);
-      assertTrue(resultSet.next());
+      // This can sometimes fail, as the mock server may not always actually return the first row.
+      try {
+        assertTrue(resultSet.next());
+      } catch (SpannerException exception) {
+        assertEquals(ErrorCode.DEADLINE_EXCEEDED, exception.getErrorCode());
+        return;
+      }
       List<ExecuteSqlRequest> executeSqlRequests =
           mockSpanner.getRequestsOfType(ExecuteSqlRequest.class).stream()
               .filter(request -> request.getSql().equals(SELECT_RANDOM_STATEMENT.getSql()))
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
index 62336163eaf..88b9c8d21e3 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
@@ -36,6 +36,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.ByteString;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryMode;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.QueryPlan;
 import com.google.spanner.v1.ResultSetMetadata;
@@ -70,6 +71,9 @@ private static class NoOpListener implements AbstractResultSet.Listener {
     public void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId)
         throws SpannerException {}
 
+    @Override
+    public void onPrecommitToken(MultiplexedSessionPrecommitToken token) {}
+
     @Override
     public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
       return e;
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadFormatTestRunner.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadFormatTestRunner.java
index c973b7e471e..1044827dbc1 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadFormatTestRunner.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadFormatTestRunner.java
@@ -24,6 +24,7 @@
 import com.google.cloud.spanner.spi.v1.SpannerRpc;
 import com.google.common.io.Resources;
 import com.google.protobuf.util.JsonFormat;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.Transaction;
 import java.math.BigDecimal;
@@ -49,6 +50,9 @@ private static class NoOpListener implements AbstractResultSet.Listener {
     public void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId)
         throws SpannerException {}
 
+    @Override
+    public void onPrecommitToken(MultiplexedSessionPrecommitToken token) {}
+
     @Override
     public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
       return e;
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ResultSetsHelper.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ResultSetsHelper.java
index fc494c6f3ff..647c0b93b98 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ResultSetsHelper.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ResultSetsHelper.java
@@ -19,6 +19,7 @@
 import com.google.cloud.spanner.AbstractResultSet.CloseableIterator;
 import com.google.cloud.spanner.AbstractResultSet.Listener;
 import com.google.protobuf.ListValue;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.Transaction;
 import java.util.Iterator;
@@ -75,6 +76,9 @@ public PartialResultSet next() {
           public void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId)
               throws SpannerException {}
 
+          @Override
+          public void onPrecommitToken(MultiplexedSessionPrecommitToken token) {}
+
           @Override
           public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
             return e;
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
index 998678e4296..becce6e0488 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
@@ -87,6 +87,7 @@
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ResultSetStats;
 import com.google.spanner.v1.RollbackRequest;
+import com.google.spanner.v1.Transaction;
 import io.opencensus.metrics.LabelValue;
 import io.opencensus.metrics.MetricRegistry;
 import io.opencensus.metrics.Metrics;
@@ -1497,7 +1498,7 @@ public void testSessionNotFoundReadWriteTransaction() {
           .thenReturn(ApiFutures.immediateFuture(Empty.getDefaultInstance()));
       when(closedSession.newTransaction(Options.fromTransactionOptions()))
           .thenReturn(closedTransactionContext);
-      when(closedSession.beginTransactionAsync(any(), eq(true), any())).thenThrow(sessionNotFound);
+      when(closedSession.beginTransactionAsync(any(), eq(true), any(), any())).thenThrow(sessionNotFound);
       when(closedSession.getTracer()).thenReturn(tracer);
       TransactionRunnerImpl closedTransactionRunner = new TransactionRunnerImpl(closedSession);
       closedTransactionRunner.setSpan(span);
@@ -1512,8 +1513,8 @@ public void testSessionNotFoundReadWriteTransaction() {
       final TransactionContextImpl openTransactionContext = mock(TransactionContextImpl.class);
       when(openSession.newTransaction(Options.fromTransactionOptions()))
           .thenReturn(openTransactionContext);
-      when(openSession.beginTransactionAsync(any(), eq(true), any()))
-          .thenReturn(ApiFutures.immediateFuture(ByteString.copyFromUtf8("open-txn")));
+      when(openSession.beginTransactionAsync(any(), eq(true), any(), any()))
+          .thenReturn(ApiFutures.immediateFuture(Transaction.getDefaultInstance()));
       when(openSession.getTracer()).thenReturn(tracer);
       TransactionRunnerImpl openTransactionRunner = new TransactionRunnerImpl(openSession);
       openTransactionRunner.setSpan(span);
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientHttpJsonTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientHttpJsonTest.java
index 3b5f106f13f..1683d533855 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientHttpJsonTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientHttpJsonTest.java
@@ -44,6 +44,7 @@
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.KeySet;
 import com.google.spanner.v1.ListSessionsResponse;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.Mutation;
 import com.google.spanner.v1.Partition;
 import com.google.spanner.v1.PartitionOptions;
@@ -587,6 +588,7 @@ public void executeSqlTest() throws Exception {
             .setMetadata(ResultSetMetadata.newBuilder().build())
             .addAllRows(new ArrayList<ListValue>())
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -673,6 +675,7 @@ public void executeBatchDmlTest() throws Exception {
         ExecuteBatchDmlResponse.newBuilder()
             .addAllResultSets(new ArrayList<ResultSet>())
             .setStatus(Status.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -735,6 +738,7 @@ public void readTest() throws Exception {
             .setMetadata(ResultSetMetadata.newBuilder().build())
             .addAllRows(new ArrayList<ListValue>())
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -821,6 +825,7 @@ public void beginTransactionTest() throws Exception {
         Transaction.newBuilder()
             .setId(ByteString.EMPTY)
             .setReadTimestamp(Timestamp.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -868,6 +873,7 @@ public void beginTransactionTest2() throws Exception {
         Transaction.newBuilder()
             .setId(ByteString.EMPTY)
             .setReadTimestamp(Timestamp.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockService.addResponse(expectedResponse);
 
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
index 22f578ac2bc..83caf7405d9 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
@@ -55,6 +55,7 @@
 import com.google.spanner.v1.KeySet;
 import com.google.spanner.v1.ListSessionsRequest;
 import com.google.spanner.v1.ListSessionsResponse;
+import com.google.spanner.v1.MultiplexedSessionPrecommitToken;
 import com.google.spanner.v1.Mutation;
 import com.google.spanner.v1.PartialResultSet;
 import com.google.spanner.v1.Partition;
@@ -545,6 +546,7 @@ public void executeSqlTest() throws Exception {
             .setMetadata(ResultSetMetadata.newBuilder().build())
             .addAllRows(new ArrayList<ListValue>())
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
 
@@ -629,6 +631,7 @@ public void executeStreamingSqlTest() throws Exception {
             .setChunkedValue(true)
             .setResumeToken(ByteString.EMPTY)
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
     ExecuteSqlRequest request =
@@ -702,6 +705,7 @@ public void executeBatchDmlTest() throws Exception {
         ExecuteBatchDmlResponse.newBuilder()
             .addAllResultSets(new ArrayList<ResultSet>())
             .setStatus(Status.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
 
@@ -762,6 +766,7 @@ public void readTest() throws Exception {
             .setMetadata(ResultSetMetadata.newBuilder().build())
             .addAllRows(new ArrayList<ListValue>())
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
 
@@ -847,6 +852,7 @@ public void streamingReadTest() throws Exception {
             .setChunkedValue(true)
             .setResumeToken(ByteString.EMPTY)
             .setStats(ResultSetStats.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
     ReadRequest request =
@@ -920,6 +926,7 @@ public void beginTransactionTest() throws Exception {
         Transaction.newBuilder()
             .setId(ByteString.EMPTY)
             .setReadTimestamp(Timestamp.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
 
@@ -962,6 +969,7 @@ public void beginTransactionTest2() throws Exception {
         Transaction.newBuilder()
             .setId(ByteString.EMPTY)
             .setReadTimestamp(Timestamp.newBuilder().build())
+            .setPrecommitToken(MultiplexedSessionPrecommitToken.newBuilder().build())
             .build();
     mockSpanner.addResponse(expectedResponse);
 
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequest.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequest.java
index c2b54d6ce94..1a564ec3f5e 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequest.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequest.java
@@ -238,6 +238,68 @@ public com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder(
         : requestOptions_;
   }
 
+  public static final int MUTATION_KEY_FIELD_NUMBER = 4;
+  private com.google.spanner.v1.Mutation mutationKey_;
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the mutationKey field is set.
+   */
+  @java.lang.Override
+  public boolean hasMutationKey() {
+    return ((bitField0_ & 0x00000004) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The mutationKey.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.Mutation getMutationKey() {
+    return mutationKey_ == null
+        ? com.google.spanner.v1.Mutation.getDefaultInstance()
+        : mutationKey_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MutationOrBuilder getMutationKeyOrBuilder() {
+    return mutationKey_ == null
+        ? com.google.spanner.v1.Mutation.getDefaultInstance()
+        : mutationKey_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -261,6 +323,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000002) != 0)) {
       output.writeMessage(3, getRequestOptions());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      output.writeMessage(4, getMutationKey());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -279,6 +344,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000002) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getRequestOptions());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, getMutationKey());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -304,6 +372,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasRequestOptions()) {
       if (!getRequestOptions().equals(other.getRequestOptions())) return false;
     }
+    if (hasMutationKey() != other.hasMutationKey()) return false;
+    if (hasMutationKey()) {
+      if (!getMutationKey().equals(other.getMutationKey())) return false;
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -325,6 +397,10 @@ public int hashCode() {
       hash = (37 * hash) + REQUEST_OPTIONS_FIELD_NUMBER;
       hash = (53 * hash) + getRequestOptions().hashCode();
     }
+    if (hasMutationKey()) {
+      hash = (37 * hash) + MUTATION_KEY_FIELD_NUMBER;
+      hash = (53 * hash) + getMutationKey().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -468,6 +544,7 @@ private void maybeForceBuilderInitialization() {
       if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
         getOptionsFieldBuilder();
         getRequestOptionsFieldBuilder();
+        getMutationKeyFieldBuilder();
       }
     }
 
@@ -486,6 +563,11 @@ public Builder clear() {
         requestOptionsBuilder_.dispose();
         requestOptionsBuilder_ = null;
       }
+      mutationKey_ = null;
+      if (mutationKeyBuilder_ != null) {
+        mutationKeyBuilder_.dispose();
+        mutationKeyBuilder_ = null;
+      }
       return this;
     }
 
@@ -535,6 +617,11 @@ private void buildPartial0(com.google.spanner.v1.BeginTransactionRequest result)
             requestOptionsBuilder_ == null ? requestOptions_ : requestOptionsBuilder_.build();
         to_bitField0_ |= 0x00000002;
       }
+      if (((from_bitField0_ & 0x00000008) != 0)) {
+        result.mutationKey_ =
+            mutationKeyBuilder_ == null ? mutationKey_ : mutationKeyBuilder_.build();
+        to_bitField0_ |= 0x00000004;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -594,6 +681,9 @@ public Builder mergeFrom(com.google.spanner.v1.BeginTransactionRequest other) {
       if (other.hasRequestOptions()) {
         mergeRequestOptions(other.getRequestOptions());
       }
+      if (other.hasMutationKey()) {
+        mergeMutationKey(other.getMutationKey());
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -638,6 +728,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000004;
                 break;
               } // case 26
+            case 34:
+              {
+                input.readMessage(getMutationKeyFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000008;
+                break;
+              } // case 34
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -1197,6 +1293,227 @@ public com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder(
       return requestOptionsBuilder_;
     }
 
+    private com.google.spanner.v1.Mutation mutationKey_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.Mutation,
+            com.google.spanner.v1.Mutation.Builder,
+            com.google.spanner.v1.MutationOrBuilder>
+        mutationKeyBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return Whether the mutationKey field is set.
+     */
+    public boolean hasMutationKey() {
+      return ((bitField0_ & 0x00000008) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The mutationKey.
+     */
+    public com.google.spanner.v1.Mutation getMutationKey() {
+      if (mutationKeyBuilder_ == null) {
+        return mutationKey_ == null
+            ? com.google.spanner.v1.Mutation.getDefaultInstance()
+            : mutationKey_;
+      } else {
+        return mutationKeyBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setMutationKey(com.google.spanner.v1.Mutation value) {
+      if (mutationKeyBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        mutationKey_ = value;
+      } else {
+        mutationKeyBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setMutationKey(com.google.spanner.v1.Mutation.Builder builderForValue) {
+      if (mutationKeyBuilder_ == null) {
+        mutationKey_ = builderForValue.build();
+      } else {
+        mutationKeyBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder mergeMutationKey(com.google.spanner.v1.Mutation value) {
+      if (mutationKeyBuilder_ == null) {
+        if (((bitField0_ & 0x00000008) != 0)
+            && mutationKey_ != null
+            && mutationKey_ != com.google.spanner.v1.Mutation.getDefaultInstance()) {
+          getMutationKeyBuilder().mergeFrom(value);
+        } else {
+          mutationKey_ = value;
+        }
+      } else {
+        mutationKeyBuilder_.mergeFrom(value);
+      }
+      if (mutationKey_ != null) {
+        bitField0_ |= 0x00000008;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder clearMutationKey() {
+      bitField0_ = (bitField0_ & ~0x00000008);
+      mutationKey_ = null;
+      if (mutationKeyBuilder_ != null) {
+        mutationKeyBuilder_.dispose();
+        mutationKeyBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.Mutation.Builder getMutationKeyBuilder() {
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return getMutationKeyFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MutationOrBuilder getMutationKeyOrBuilder() {
+      if (mutationKeyBuilder_ != null) {
+        return mutationKeyBuilder_.getMessageOrBuilder();
+      } else {
+        return mutationKey_ == null
+            ? com.google.spanner.v1.Mutation.getDefaultInstance()
+            : mutationKey_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Required for read-write transactions on a multiplexed session that commit
+     * mutations but do not perform any reads or queries.
+     * Clients should randomly select one of the mutations from the
+     * mutation set and send it as a part of this request.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.Mutation,
+            com.google.spanner.v1.Mutation.Builder,
+            com.google.spanner.v1.MutationOrBuilder>
+        getMutationKeyFieldBuilder() {
+      if (mutationKeyBuilder_ == null) {
+        mutationKeyBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.Mutation,
+                com.google.spanner.v1.Mutation.Builder,
+                com.google.spanner.v1.MutationOrBuilder>(
+                getMutationKey(), getParentForChildren(), isClean());
+        mutationKey_ = null;
+      }
+      return mutationKeyBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequestOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequestOrBuilder.java
index f42a87a9df1..ceb5120da18 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequestOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/BeginTransactionRequestOrBuilder.java
@@ -140,4 +140,51 @@ public interface BeginTransactionRequestOrBuilder
    * <code>.google.spanner.v1.RequestOptions request_options = 3;</code>
    */
   com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the mutationKey field is set.
+   */
+  boolean hasMutationKey();
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The mutationKey.
+   */
+  com.google.spanner.v1.Mutation getMutationKey();
+  /**
+   *
+   *
+   * <pre>
+   * Required for read-write transactions on a multiplexed session that commit
+   * mutations but do not perform any reads or queries.
+   * Clients should randomly select one of the mutations from the
+   * mutation set and send it as a part of this request.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.Mutation mutation_key = 4 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  com.google.spanner.v1.MutationOrBuilder getMutationKeyOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
index cd3f62a2438..d17d62d3da4 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
@@ -495,6 +495,72 @@ public com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder(
         : requestOptions_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 9;
+  private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return ((bitField0_ & 0x00000004) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -530,6 +596,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000001) != 0)) {
       output.writeMessage(8, getMaxCommitDelay());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      output.writeMessage(9, getPrecommitToken());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -564,6 +633,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000001) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(8, getMaxCommitDelay());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(9, getPrecommitToken());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -590,6 +662,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasRequestOptions()) {
       if (!getRequestOptions().equals(other.getRequestOptions())) return false;
     }
+    if (hasPrecommitToken() != other.hasPrecommitToken()) return false;
+    if (hasPrecommitToken()) {
+      if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    }
     if (!getTransactionCase().equals(other.getTransactionCase())) return false;
     switch (transactionCase_) {
       case 2:
@@ -628,6 +704,10 @@ public int hashCode() {
       hash = (37 * hash) + REQUEST_OPTIONS_FIELD_NUMBER;
       hash = (53 * hash) + getRequestOptions().hashCode();
     }
+    if (hasPrecommitToken()) {
+      hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+      hash = (53 * hash) + getPrecommitToken().hashCode();
+    }
     switch (transactionCase_) {
       case 2:
         hash = (37 * hash) + TRANSACTION_ID_FIELD_NUMBER;
@@ -782,6 +862,7 @@ private void maybeForceBuilderInitialization() {
         getMutationsFieldBuilder();
         getMaxCommitDelayFieldBuilder();
         getRequestOptionsFieldBuilder();
+        getPrecommitTokenFieldBuilder();
       }
     }
 
@@ -811,6 +892,11 @@ public Builder clear() {
         requestOptionsBuilder_.dispose();
         requestOptionsBuilder_ = null;
       }
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
       transactionCase_ = 0;
       transaction_ = null;
       return this;
@@ -879,6 +965,11 @@ private void buildPartial0(com.google.spanner.v1.CommitRequest result) {
             requestOptionsBuilder_ == null ? requestOptions_ : requestOptionsBuilder_.build();
         to_bitField0_ |= 0x00000002;
       }
+      if (((from_bitField0_ & 0x00000080) != 0)) {
+        result.precommitToken_ =
+            precommitTokenBuilder_ == null ? precommitToken_ : precommitTokenBuilder_.build();
+        to_bitField0_ |= 0x00000004;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -976,6 +1067,9 @@ public Builder mergeFrom(com.google.spanner.v1.CommitRequest other) {
       if (other.hasRequestOptions()) {
         mergeRequestOptions(other.getRequestOptions());
       }
+      if (other.hasPrecommitToken()) {
+        mergePrecommitToken(other.getPrecommitToken());
+      }
       switch (other.getTransactionCase()) {
         case TRANSACTION_ID:
           {
@@ -1067,6 +1161,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000020;
                 break;
               } // case 66
+            case 74:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000080;
+                break;
+              } // case 74
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -2434,6 +2534,241 @@ public com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder(
       return requestOptionsBuilder_;
     }
 
+    private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    public boolean hasPrecommitToken() {
+      return ((bitField0_ & 0x00000080) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The precommitToken.
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      } else {
+        return precommitTokenBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        precommitToken_ = value;
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000080;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        precommitToken_ = builderForValue.build();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000080;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (((bitField0_ & 0x00000080) != 0)
+            && precommitToken_ != null
+            && precommitToken_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          getPrecommitTokenBuilder().mergeFrom(value);
+        } else {
+          precommitToken_ = value;
+        }
+      } else {
+        precommitTokenBuilder_.mergeFrom(value);
+      }
+      if (precommitToken_ != null) {
+        bitField0_ |= 0x00000080;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000080);
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      bitField0_ |= 0x00000080;
+      onChanged();
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if (precommitTokenBuilder_ != null) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If the read-write transaction was executed on a multiplexed session, the
+     * precommit token with the highest sequence number received
+     * in this transaction attempt, should be included here.
+     * Failing to do so will result in a FailedPrecondition error.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                getPrecommitToken(), getParentForChildren(), isClean());
+        precommitToken_ = null;
+      }
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
index ed19e5568e0..6974bb845d4 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
@@ -298,5 +298,55 @@ public interface CommitRequestOrBuilder
    */
   com.google.spanner.v1.RequestOptionsOrBuilder getRequestOptionsOrBuilder();
 
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * If the read-write transaction was executed on a multiplexed session, the
+   * precommit token with the highest sequence number received
+   * in this transaction attempt, should be included here.
+   * Failing to do so will result in a FailedPrecondition error.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 9 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
+
   com.google.spanner.v1.CommitRequest.TransactionCase getTransactionCase();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
index 05ae3b23bfc..f25539a148e 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
@@ -631,6 +631,52 @@ public com.google.spanner.v1.CommitResponse.CommitStats getDefaultInstanceForTyp
   }
 
   private int bitField0_;
+  private int multiplexedSessionRetryCase_ = 0;
+
+  @SuppressWarnings("serial")
+  private java.lang.Object multiplexedSessionRetry_;
+
+  public enum MultiplexedSessionRetryCase
+      implements
+          com.google.protobuf.Internal.EnumLite,
+          com.google.protobuf.AbstractMessage.InternalOneOfEnum {
+    PRECOMMIT_TOKEN(4),
+    MULTIPLEXEDSESSIONRETRY_NOT_SET(0);
+    private final int value;
+
+    private MultiplexedSessionRetryCase(int value) {
+      this.value = value;
+    }
+    /**
+     * @param value The number of the enum to look for.
+     * @return The enum associated with the given number.
+     * @deprecated Use {@link #forNumber(int)} instead.
+     */
+    @java.lang.Deprecated
+    public static MultiplexedSessionRetryCase valueOf(int value) {
+      return forNumber(value);
+    }
+
+    public static MultiplexedSessionRetryCase forNumber(int value) {
+      switch (value) {
+        case 4:
+          return PRECOMMIT_TOKEN;
+        case 0:
+          return MULTIPLEXEDSESSIONRETRY_NOT_SET;
+        default:
+          return null;
+      }
+    }
+
+    public int getNumber() {
+      return this.value;
+    }
+  };
+
+  public MultiplexedSessionRetryCase getMultiplexedSessionRetryCase() {
+    return MultiplexedSessionRetryCase.forNumber(multiplexedSessionRetryCase_);
+  }
+
   public static final int COMMIT_TIMESTAMP_FIELD_NUMBER = 1;
   private com.google.protobuf.Timestamp commitTimestamp_;
   /**
@@ -737,6 +783,61 @@ public com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsO
         : commitStats_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 4;
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return multiplexedSessionRetryCase_ == 4;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    if (multiplexedSessionRetryCase_ == 4) {
+      return (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_;
+    }
+    return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+  }
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    if (multiplexedSessionRetryCase_ == 4) {
+      return (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_;
+    }
+    return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -757,6 +858,10 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000002) != 0)) {
       output.writeMessage(2, getCommitStats());
     }
+    if (multiplexedSessionRetryCase_ == 4) {
+      output.writeMessage(
+          4, (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_);
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -772,6 +877,11 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000002) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, getCommitStats());
     }
+    if (multiplexedSessionRetryCase_ == 4) {
+      size +=
+          com.google.protobuf.CodedOutputStream.computeMessageSize(
+              4, (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_);
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -795,6 +905,15 @@ public boolean equals(final java.lang.Object obj) {
     if (hasCommitStats()) {
       if (!getCommitStats().equals(other.getCommitStats())) return false;
     }
+    if (!getMultiplexedSessionRetryCase().equals(other.getMultiplexedSessionRetryCase()))
+      return false;
+    switch (multiplexedSessionRetryCase_) {
+      case 4:
+        if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+        break;
+      case 0:
+      default:
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -814,6 +933,14 @@ public int hashCode() {
       hash = (37 * hash) + COMMIT_STATS_FIELD_NUMBER;
       hash = (53 * hash) + getCommitStats().hashCode();
     }
+    switch (multiplexedSessionRetryCase_) {
+      case 4:
+        hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+        hash = (53 * hash) + getPrecommitToken().hashCode();
+        break;
+      case 0:
+      default:
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -972,6 +1099,11 @@ public Builder clear() {
         commitStatsBuilder_.dispose();
         commitStatsBuilder_ = null;
       }
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.clear();
+      }
+      multiplexedSessionRetryCase_ = 0;
+      multiplexedSessionRetry_ = null;
       return this;
     }
 
@@ -1001,6 +1133,7 @@ public com.google.spanner.v1.CommitResponse buildPartial() {
       if (bitField0_ != 0) {
         buildPartial0(result);
       }
+      buildPartialOneofs(result);
       onBuilt();
       return result;
     }
@@ -1021,6 +1154,14 @@ private void buildPartial0(com.google.spanner.v1.CommitResponse result) {
       result.bitField0_ |= to_bitField0_;
     }
 
+    private void buildPartialOneofs(com.google.spanner.v1.CommitResponse result) {
+      result.multiplexedSessionRetryCase_ = multiplexedSessionRetryCase_;
+      result.multiplexedSessionRetry_ = this.multiplexedSessionRetry_;
+      if (multiplexedSessionRetryCase_ == 4 && precommitTokenBuilder_ != null) {
+        result.multiplexedSessionRetry_ = precommitTokenBuilder_.build();
+      }
+    }
+
     @java.lang.Override
     public Builder clone() {
       return super.clone();
@@ -1072,6 +1213,17 @@ public Builder mergeFrom(com.google.spanner.v1.CommitResponse other) {
       if (other.hasCommitStats()) {
         mergeCommitStats(other.getCommitStats());
       }
+      switch (other.getMultiplexedSessionRetryCase()) {
+        case PRECOMMIT_TOKEN:
+          {
+            mergePrecommitToken(other.getPrecommitToken());
+            break;
+          }
+        case MULTIPLEXEDSESSIONRETRY_NOT_SET:
+          {
+            break;
+          }
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -1110,6 +1262,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000002;
                 break;
               } // case 18
+            case 34:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                multiplexedSessionRetryCase_ = 4;
+                break;
+              } // case 34
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -1127,6 +1285,20 @@ public Builder mergeFrom(
       return this;
     }
 
+    private int multiplexedSessionRetryCase_ = 0;
+    private java.lang.Object multiplexedSessionRetry_;
+
+    public MultiplexedSessionRetryCase getMultiplexedSessionRetryCase() {
+      return MultiplexedSessionRetryCase.forNumber(multiplexedSessionRetryCase_);
+    }
+
+    public Builder clearMultiplexedSessionRetry() {
+      multiplexedSessionRetryCase_ = 0;
+      multiplexedSessionRetry_ = null;
+      onChanged();
+      return this;
+    }
+
     private int bitField0_;
 
     private com.google.protobuf.Timestamp commitTimestamp_;
@@ -1519,6 +1691,230 @@ public com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsO
       return commitStatsBuilder_;
     }
 
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    @java.lang.Override
+    public boolean hasPrecommitToken() {
+      return multiplexedSessionRetryCase_ == 4;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     *
+     * @return The precommitToken.
+     */
+    @java.lang.Override
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        if (multiplexedSessionRetryCase_ == 4) {
+          return (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_;
+        }
+        return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+      } else {
+        if (multiplexedSessionRetryCase_ == 4) {
+          return precommitTokenBuilder_.getMessage();
+        }
+        return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        multiplexedSessionRetry_ = value;
+        onChanged();
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      multiplexedSessionRetryCase_ = 4;
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        multiplexedSessionRetry_ = builderForValue.build();
+        onChanged();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      multiplexedSessionRetryCase_ = 4;
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (multiplexedSessionRetryCase_ == 4
+            && multiplexedSessionRetry_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          multiplexedSessionRetry_ =
+              com.google.spanner.v1.MultiplexedSessionPrecommitToken.newBuilder(
+                      (com.google.spanner.v1.MultiplexedSessionPrecommitToken)
+                          multiplexedSessionRetry_)
+                  .mergeFrom(value)
+                  .buildPartial();
+        } else {
+          multiplexedSessionRetry_ = value;
+        }
+        onChanged();
+      } else {
+        if (multiplexedSessionRetryCase_ == 4) {
+          precommitTokenBuilder_.mergeFrom(value);
+        } else {
+          precommitTokenBuilder_.setMessage(value);
+        }
+      }
+      multiplexedSessionRetryCase_ = 4;
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    public Builder clearPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        if (multiplexedSessionRetryCase_ == 4) {
+          multiplexedSessionRetryCase_ = 0;
+          multiplexedSessionRetry_ = null;
+          onChanged();
+        }
+      } else {
+        if (multiplexedSessionRetryCase_ == 4) {
+          multiplexedSessionRetryCase_ = 0;
+          multiplexedSessionRetry_ = null;
+        }
+        precommitTokenBuilder_.clear();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    @java.lang.Override
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if ((multiplexedSessionRetryCase_ == 4) && (precommitTokenBuilder_ != null)) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        if (multiplexedSessionRetryCase_ == 4) {
+          return (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_;
+        }
+        return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If specified, transaction has not committed yet.
+     * Clients must retry the commit with the new precommit token.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        if (!(multiplexedSessionRetryCase_ == 4)) {
+          multiplexedSessionRetry_ =
+              com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+        }
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                (com.google.spanner.v1.MultiplexedSessionPrecommitToken) multiplexedSessionRetry_,
+                getParentForChildren(),
+                isClean());
+        multiplexedSessionRetry_ = null;
+      }
+      multiplexedSessionRetryCase_ = 4;
+      onChanged();
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
index e21b58a3dfe..247605af06c 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
@@ -99,4 +99,44 @@ public interface CommitResponseOrBuilder
    * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
    */
   com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * If specified, transaction has not committed yet.
+   * Clients must retry the commit with the new precommit token.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 4;</code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
+
+  com.google.spanner.v1.CommitResponse.MultiplexedSessionRetryCase getMultiplexedSessionRetryCase();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseProto.java
index 6a0c06b8018..292218c245b 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseProto.java
@@ -47,22 +47,27 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     java.lang.String[] descriptorData = {
       "\n\'google/spanner/v1/commit_response.prot"
           + "o\022\021google.spanner.v1\032\037google/protobuf/ti"
-          + "mestamp.proto\"\262\001\n\016CommitResponse\0224\n\020comm"
-          + "it_timestamp\030\001 \001(\0132\032.google.protobuf.Tim"
-          + "estamp\022C\n\014commit_stats\030\002 \001(\0132-.google.sp"
-          + "anner.v1.CommitResponse.CommitStats\032%\n\013C"
-          + "ommitStats\022\026\n\016mutation_count\030\001 \001(\003B\266\001\n\025c"
-          + "om.google.spanner.v1B\023CommitResponseProt"
-          + "oP\001Z5cloud.google.com/go/spanner/apiv1/s"
-          + "pannerpb;spannerpb\252\002\027Google.Cloud.Spanne"
-          + "r.V1\312\002\027Google\\Cloud\\Spanner\\V1\352\002\032Google:"
-          + ":Cloud::Spanner::V1b\006proto3"
+          + "mestamp.proto\032#google/spanner/v1/transac"
+          + "tion.proto\"\235\002\n\016CommitResponse\0224\n\020commit_"
+          + "timestamp\030\001 \001(\0132\032.google.protobuf.Timest"
+          + "amp\022C\n\014commit_stats\030\002 \001(\0132-.google.spann"
+          + "er.v1.CommitResponse.CommitStats\022N\n\017prec"
+          + "ommit_token\030\004 \001(\01323.google.spanner.v1.Mu"
+          + "ltiplexedSessionPrecommitTokenH\000\032%\n\013Comm"
+          + "itStats\022\026\n\016mutation_count\030\001 \001(\003B\031\n\027Multi"
+          + "plexedSessionRetryB\266\001\n\025com.google.spanne"
+          + "r.v1B\023CommitResponseProtoP\001Z5cloud.googl"
+          + "e.com/go/spanner/apiv1/spannerpb;spanner"
+          + "pb\252\002\027Google.Cloud.Spanner.V1\312\002\027Google\\Cl"
+          + "oud\\Spanner\\V1\352\002\032Google::Cloud::Spanner:"
+          + ":V1b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
             descriptorData,
             new com.google.protobuf.Descriptors.FileDescriptor[] {
               com.google.protobuf.TimestampProto.getDescriptor(),
+              com.google.spanner.v1.TransactionProto.getDescriptor(),
             });
     internal_static_google_spanner_v1_CommitResponse_descriptor =
         getDescriptor().getMessageTypes().get(0);
@@ -70,7 +75,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_CommitResponse_descriptor,
             new java.lang.String[] {
-              "CommitTimestamp", "CommitStats",
+              "CommitTimestamp", "CommitStats", "PrecommitToken", "MultiplexedSessionRetry",
             });
     internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor =
         internal_static_google_spanner_v1_CommitResponse_descriptor.getNestedTypes().get(0);
@@ -81,6 +86,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
               "MutationCount",
             });
     com.google.protobuf.TimestampProto.getDescriptor();
+    com.google.spanner.v1.TransactionProto.getDescriptor();
   }
 
   // @@protoc_insertion_point(outer_class_scope)
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponse.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponse.java
index f60631a1097..9a818adecab 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponse.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponse.java
@@ -254,6 +254,75 @@ public com.google.rpc.StatusOrBuilder getStatusOrBuilder() {
     return status_ == null ? com.google.rpc.Status.getDefaultInstance() : status_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 3;
+  private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return ((bitField0_ & 0x00000002) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -274,6 +343,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000001) != 0)) {
       output.writeMessage(2, getStatus());
     }
+    if (((bitField0_ & 0x00000002) != 0)) {
+      output.writeMessage(3, getPrecommitToken());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -289,6 +361,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000001) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, getStatus());
     }
+    if (((bitField0_ & 0x00000002) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getPrecommitToken());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -310,6 +385,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasStatus()) {
       if (!getStatus().equals(other.getStatus())) return false;
     }
+    if (hasPrecommitToken() != other.hasPrecommitToken()) return false;
+    if (hasPrecommitToken()) {
+      if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -329,6 +408,10 @@ public int hashCode() {
       hash = (37 * hash) + STATUS_FIELD_NUMBER;
       hash = (53 * hash) + getStatus().hashCode();
     }
+    if (hasPrecommitToken()) {
+      hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+      hash = (53 * hash) + getPrecommitToken().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -501,6 +584,7 @@ private void maybeForceBuilderInitialization() {
       if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
         getResultSetsFieldBuilder();
         getStatusFieldBuilder();
+        getPrecommitTokenFieldBuilder();
       }
     }
 
@@ -520,6 +604,11 @@ public Builder clear() {
         statusBuilder_.dispose();
         statusBuilder_ = null;
       }
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
       return this;
     }
 
@@ -574,6 +663,11 @@ private void buildPartial0(com.google.spanner.v1.ExecuteBatchDmlResponse result)
         result.status_ = statusBuilder_ == null ? status_ : statusBuilder_.build();
         to_bitField0_ |= 0x00000001;
       }
+      if (((from_bitField0_ & 0x00000004) != 0)) {
+        result.precommitToken_ =
+            precommitTokenBuilder_ == null ? precommitToken_ : precommitTokenBuilder_.build();
+        to_bitField0_ |= 0x00000002;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -652,6 +746,9 @@ public Builder mergeFrom(com.google.spanner.v1.ExecuteBatchDmlResponse other) {
       if (other.hasStatus()) {
         mergeStatus(other.getStatus());
       }
+      if (other.hasPrecommitToken()) {
+        mergePrecommitToken(other.getPrecommitToken());
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -696,6 +793,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000002;
                 break;
               } // case 18
+            case 26:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000004;
+                break;
+              } // case 26
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -1392,6 +1495,250 @@ public com.google.rpc.StatusOrBuilder getStatusOrBuilder() {
       return statusBuilder_;
     }
 
+    private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    public boolean hasPrecommitToken() {
+      return ((bitField0_ & 0x00000004) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The precommitToken.
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      } else {
+        return precommitTokenBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        precommitToken_ = value;
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        precommitToken_ = builderForValue.build();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (((bitField0_ & 0x00000004) != 0)
+            && precommitToken_ != null
+            && precommitToken_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          getPrecommitTokenBuilder().mergeFrom(value);
+        } else {
+          precommitToken_ = value;
+        }
+      } else {
+        precommitTokenBuilder_.mergeFrom(value);
+      }
+      if (precommitToken_ != null) {
+        bitField0_ |= 0x00000004;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000004);
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if (precommitTokenBuilder_ != null) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                getPrecommitToken(), getParentForChildren(), isClean());
+        precommitToken_ = null;
+      }
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponseOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponseOrBuilder.java
index cac2a088624..551359460c3 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponseOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteBatchDmlResponseOrBuilder.java
@@ -152,4 +152,57 @@ public interface ExecuteBatchDmlResponseOrBuilder
    * <code>.google.rpc.Status status = 2;</code>
    */
   com.google.rpc.StatusOrBuilder getStatusOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitToken.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitToken.java
new file mode 100644
index 00000000000..e3538ba992b
--- /dev/null
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitToken.java
@@ -0,0 +1,648 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/spanner/v1/transaction.proto
+
+// Protobuf Java Version: 3.25.3
+package com.google.spanner.v1;
+
+/**
+ *
+ *
+ * <pre>
+ * When a read-write transaction is executed on a multiplexed session,
+ * this precommit token is sent back to the client
+ * as a part of the [Transaction] message in the BeginTransaction response and
+ * also as a part of the [ResultSet] and [PartialResultSet] responses.
+ * </pre>
+ *
+ * Protobuf type {@code google.spanner.v1.MultiplexedSessionPrecommitToken}
+ */
+public final class MultiplexedSessionPrecommitToken extends com.google.protobuf.GeneratedMessageV3
+    implements
+    // @@protoc_insertion_point(message_implements:google.spanner.v1.MultiplexedSessionPrecommitToken)
+    MultiplexedSessionPrecommitTokenOrBuilder {
+  private static final long serialVersionUID = 0L;
+  // Use MultiplexedSessionPrecommitToken.newBuilder() to construct.
+  private MultiplexedSessionPrecommitToken(
+      com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+
+  private MultiplexedSessionPrecommitToken() {
+    precommitToken_ = com.google.protobuf.ByteString.EMPTY;
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(UnusedPrivateParameter unused) {
+    return new MultiplexedSessionPrecommitToken();
+  }
+
+  public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+    return com.google.spanner.v1.TransactionProto
+        .internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return com.google.spanner.v1.TransactionProto
+        .internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.class,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder.class);
+  }
+
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 1;
+  private com.google.protobuf.ByteString precommitToken_ = com.google.protobuf.ByteString.EMPTY;
+  /**
+   *
+   *
+   * <pre>
+   * Opaque precommit token.
+   * </pre>
+   *
+   * <code>bytes precommit_token = 1;</code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString getPrecommitToken() {
+    return precommitToken_;
+  }
+
+  public static final int SEQ_NUM_FIELD_NUMBER = 2;
+  private int seqNum_ = 0;
+  /**
+   *
+   *
+   * <pre>
+   * An incrementing seq number is generated on every precommit token
+   * that is returned. Clients should remember the precommit token with the
+   * highest sequence number from the current transaction attempt.
+   * </pre>
+   *
+   * <code>int32 seq_num = 2;</code>
+   *
+   * @return The seqNum.
+   */
+  @java.lang.Override
+  public int getSeqNum() {
+    return seqNum_;
+  }
+
+  private byte memoizedIsInitialized = -1;
+
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
+    if (!precommitToken_.isEmpty()) {
+      output.writeBytes(1, precommitToken_);
+    }
+    if (seqNum_ != 0) {
+      output.writeInt32(2, seqNum_);
+    }
+    getUnknownFields().writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (!precommitToken_.isEmpty()) {
+      size += com.google.protobuf.CodedOutputStream.computeBytesSize(1, precommitToken_);
+    }
+    if (seqNum_ != 0) {
+      size += com.google.protobuf.CodedOutputStream.computeInt32Size(2, seqNum_);
+    }
+    size += getUnknownFields().getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (!(obj instanceof com.google.spanner.v1.MultiplexedSessionPrecommitToken)) {
+      return super.equals(obj);
+    }
+    com.google.spanner.v1.MultiplexedSessionPrecommitToken other =
+        (com.google.spanner.v1.MultiplexedSessionPrecommitToken) obj;
+
+    if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    if (getSeqNum() != other.getSeqNum()) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+    hash = (53 * hash) + getPrecommitToken().hashCode();
+    hash = (37 * hash) + SEQ_NUM_FIELD_NUMBER;
+    hash = (53 * hash) + getSeqNum();
+    hash = (29 * hash) + getUnknownFields().hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      java.nio.ByteBuffer data) throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      java.nio.ByteBuffer data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      byte[] data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      java.io.InputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseDelimitedFrom(
+      java.io.InputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseDelimitedFrom(
+      java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      com.google.protobuf.CodedInputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() {
+    return newBuilder();
+  }
+
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+
+  public static Builder newBuilder(
+      com.google.spanner.v1.MultiplexedSessionPrecommitToken prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * When a read-write transaction is executed on a multiplexed session,
+   * this precommit token is sent back to the client
+   * as a part of the [Transaction] message in the BeginTransaction response and
+   * also as a part of the [ResultSet] and [PartialResultSet] responses.
+   * </pre>
+   *
+   * Protobuf type {@code google.spanner.v1.MultiplexedSessionPrecommitToken}
+   */
+  public static final class Builder extends com.google.protobuf.GeneratedMessageV3.Builder<Builder>
+      implements
+      // @@protoc_insertion_point(builder_implements:google.spanner.v1.MultiplexedSessionPrecommitToken)
+      com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+      return com.google.spanner.v1.TransactionProto
+          .internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return com.google.spanner.v1.TransactionProto
+          .internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              com.google.spanner.v1.MultiplexedSessionPrecommitToken.class,
+              com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder.class);
+    }
+
+    // Construct using com.google.spanner.v1.MultiplexedSessionPrecommitToken.newBuilder()
+    private Builder() {}
+
+    private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+    }
+
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      bitField0_ = 0;
+      precommitToken_ = com.google.protobuf.ByteString.EMPTY;
+      seqNum_ = 0;
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor getDescriptorForType() {
+      return com.google.spanner.v1.TransactionProto
+          .internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor;
+    }
+
+    @java.lang.Override
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getDefaultInstanceForType() {
+      return com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken build() {
+      com.google.spanner.v1.MultiplexedSessionPrecommitToken result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken buildPartial() {
+      com.google.spanner.v1.MultiplexedSessionPrecommitToken result =
+          new com.google.spanner.v1.MultiplexedSessionPrecommitToken(this);
+      if (bitField0_ != 0) {
+        buildPartial0(result);
+      }
+      onBuilt();
+      return result;
+    }
+
+    private void buildPartial0(com.google.spanner.v1.MultiplexedSessionPrecommitToken result) {
+      int from_bitField0_ = bitField0_;
+      if (((from_bitField0_ & 0x00000001) != 0)) {
+        result.precommitToken_ = precommitToken_;
+      }
+      if (((from_bitField0_ & 0x00000002) != 0)) {
+        result.seqNum_ = seqNum_;
+      }
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+      return super.setField(field, value);
+    }
+
+    @java.lang.Override
+    public Builder clearField(com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+
+    @java.lang.Override
+    public Builder clearOneof(com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof com.google.spanner.v1.MultiplexedSessionPrecommitToken) {
+        return mergeFrom((com.google.spanner.v1.MultiplexedSessionPrecommitToken) other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(com.google.spanner.v1.MultiplexedSessionPrecommitToken other) {
+      if (other == com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance())
+        return this;
+      if (other.getPrecommitToken() != com.google.protobuf.ByteString.EMPTY) {
+        setPrecommitToken(other.getPrecommitToken());
+      }
+      if (other.getSeqNum() != 0) {
+        setSeqNum(other.getSeqNum());
+      }
+      this.mergeUnknownFields(other.getUnknownFields());
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                precommitToken_ = input.readBytes();
+                bitField0_ |= 0x00000001;
+                break;
+              } // case 10
+            case 16:
+              {
+                seqNum_ = input.readInt32();
+                bitField0_ |= 0x00000002;
+                break;
+              } // case 16
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        throw e.unwrapIOException();
+      } finally {
+        onChanged();
+      } // finally
+      return this;
+    }
+
+    private int bitField0_;
+
+    private com.google.protobuf.ByteString precommitToken_ = com.google.protobuf.ByteString.EMPTY;
+    /**
+     *
+     *
+     * <pre>
+     * Opaque precommit token.
+     * </pre>
+     *
+     * <code>bytes precommit_token = 1;</code>
+     *
+     * @return The precommitToken.
+     */
+    @java.lang.Override
+    public com.google.protobuf.ByteString getPrecommitToken() {
+      return precommitToken_;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Opaque precommit token.
+     * </pre>
+     *
+     * <code>bytes precommit_token = 1;</code>
+     *
+     * @param value The precommitToken to set.
+     * @return This builder for chaining.
+     */
+    public Builder setPrecommitToken(com.google.protobuf.ByteString value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+      precommitToken_ = value;
+      bitField0_ |= 0x00000001;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Opaque precommit token.
+     * </pre>
+     *
+     * <code>bytes precommit_token = 1;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000001);
+      precommitToken_ = getDefaultInstance().getPrecommitToken();
+      onChanged();
+      return this;
+    }
+
+    private int seqNum_;
+    /**
+     *
+     *
+     * <pre>
+     * An incrementing seq number is generated on every precommit token
+     * that is returned. Clients should remember the precommit token with the
+     * highest sequence number from the current transaction attempt.
+     * </pre>
+     *
+     * <code>int32 seq_num = 2;</code>
+     *
+     * @return The seqNum.
+     */
+    @java.lang.Override
+    public int getSeqNum() {
+      return seqNum_;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * An incrementing seq number is generated on every precommit token
+     * that is returned. Clients should remember the precommit token with the
+     * highest sequence number from the current transaction attempt.
+     * </pre>
+     *
+     * <code>int32 seq_num = 2;</code>
+     *
+     * @param value The seqNum to set.
+     * @return This builder for chaining.
+     */
+    public Builder setSeqNum(int value) {
+
+      seqNum_ = value;
+      bitField0_ |= 0x00000002;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * An incrementing seq number is generated on every precommit token
+     * that is returned. Clients should remember the precommit token with the
+     * highest sequence number from the current transaction attempt.
+     * </pre>
+     *
+     * <code>int32 seq_num = 2;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearSeqNum() {
+      bitField0_ = (bitField0_ & ~0x00000002);
+      seqNum_ = 0;
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+    // @@protoc_insertion_point(builder_scope:google.spanner.v1.MultiplexedSessionPrecommitToken)
+  }
+
+  // @@protoc_insertion_point(class_scope:google.spanner.v1.MultiplexedSessionPrecommitToken)
+  private static final com.google.spanner.v1.MultiplexedSessionPrecommitToken DEFAULT_INSTANCE;
+
+  static {
+    DEFAULT_INSTANCE = new com.google.spanner.v1.MultiplexedSessionPrecommitToken();
+  }
+
+  public static com.google.spanner.v1.MultiplexedSessionPrecommitToken getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<MultiplexedSessionPrecommitToken> PARSER =
+      new com.google.protobuf.AbstractParser<MultiplexedSessionPrecommitToken>() {
+        @java.lang.Override
+        public MultiplexedSessionPrecommitToken parsePartialFrom(
+            com.google.protobuf.CodedInputStream input,
+            com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+            throws com.google.protobuf.InvalidProtocolBufferException {
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
+        }
+      };
+
+  public static com.google.protobuf.Parser<MultiplexedSessionPrecommitToken> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<MultiplexedSessionPrecommitToken> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+}
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitTokenOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitTokenOrBuilder.java
new file mode 100644
index 00000000000..31caeab1b31
--- /dev/null
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/MultiplexedSessionPrecommitTokenOrBuilder.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/spanner/v1/transaction.proto
+
+// Protobuf Java Version: 3.25.3
+package com.google.spanner.v1;
+
+public interface MultiplexedSessionPrecommitTokenOrBuilder
+    extends
+    // @@protoc_insertion_point(interface_extends:google.spanner.v1.MultiplexedSessionPrecommitToken)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   *
+   *
+   * <pre>
+   * Opaque precommit token.
+   * </pre>
+   *
+   * <code>bytes precommit_token = 1;</code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.protobuf.ByteString getPrecommitToken();
+
+  /**
+   *
+   *
+   * <pre>
+   * An incrementing seq number is generated on every precommit token
+   * that is returned. Clients should remember the precommit token with the
+   * highest sequence number from the current transaction attempt.
+   * </pre>
+   *
+   * <code>int32 seq_num = 2;</code>
+   *
+   * @return The seqNum.
+   */
+  int getSeqNum();
+}
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSet.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSet.java
index 9cd2a3dca19..403a61b5231 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSet.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSet.java
@@ -653,6 +653,75 @@ public com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder() {
     return stats_ == null ? com.google.spanner.v1.ResultSetStats.getDefaultInstance() : stats_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 8;
+  private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return ((bitField0_ & 0x00000004) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -682,6 +751,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000002) != 0)) {
       output.writeMessage(5, getStats());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      output.writeMessage(8, getPrecommitToken());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -706,6 +778,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000002) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(5, getStats());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(8, getPrecommitToken());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -732,6 +807,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasStats()) {
       if (!getStats().equals(other.getStats())) return false;
     }
+    if (hasPrecommitToken() != other.hasPrecommitToken()) return false;
+    if (hasPrecommitToken()) {
+      if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -759,6 +838,10 @@ public int hashCode() {
       hash = (37 * hash) + STATS_FIELD_NUMBER;
       hash = (53 * hash) + getStats().hashCode();
     }
+    if (hasPrecommitToken()) {
+      hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+      hash = (53 * hash) + getPrecommitToken().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -904,6 +987,7 @@ private void maybeForceBuilderInitialization() {
         getMetadataFieldBuilder();
         getValuesFieldBuilder();
         getStatsFieldBuilder();
+        getPrecommitTokenFieldBuilder();
       }
     }
 
@@ -930,6 +1014,11 @@ public Builder clear() {
         statsBuilder_.dispose();
         statsBuilder_ = null;
       }
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
       return this;
     }
 
@@ -994,6 +1083,11 @@ private void buildPartial0(com.google.spanner.v1.PartialResultSet result) {
         result.stats_ = statsBuilder_ == null ? stats_ : statsBuilder_.build();
         to_bitField0_ |= 0x00000002;
       }
+      if (((from_bitField0_ & 0x00000020) != 0)) {
+        result.precommitToken_ =
+            precommitTokenBuilder_ == null ? precommitToken_ : precommitTokenBuilder_.build();
+        to_bitField0_ |= 0x00000004;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -1081,6 +1175,9 @@ public Builder mergeFrom(com.google.spanner.v1.PartialResultSet other) {
       if (other.hasStats()) {
         mergeStats(other.getStats());
       }
+      if (other.hasPrecommitToken()) {
+        mergePrecommitToken(other.getPrecommitToken());
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -1143,6 +1240,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000010;
                 break;
               } // case 42
+            case 66:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000020;
+                break;
+              } // case 66
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -3346,6 +3449,250 @@ public com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder() {
       return statsBuilder_;
     }
 
+    private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    public boolean hasPrecommitToken() {
+      return ((bitField0_ & 0x00000020) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The precommitToken.
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      } else {
+        return precommitTokenBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        precommitToken_ = value;
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000020;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        precommitToken_ = builderForValue.build();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000020;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (((bitField0_ & 0x00000020) != 0)
+            && precommitToken_ != null
+            && precommitToken_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          getPrecommitTokenBuilder().mergeFrom(value);
+        } else {
+          precommitToken_ = value;
+        }
+      } else {
+        precommitTokenBuilder_.mergeFrom(value);
+      }
+      if (precommitToken_ != null) {
+        bitField0_ |= 0x00000020;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000020);
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      bitField0_ |= 0x00000020;
+      onChanged();
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if (precommitTokenBuilder_ != null) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                getPrecommitToken(), getParentForChildren(), isClean());
+        precommitToken_ = null;
+      }
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSetOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSetOrBuilder.java
index 2e743fd893e..d5f8aecc044 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSetOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/PartialResultSetOrBuilder.java
@@ -554,4 +554,57 @@ public interface PartialResultSetOrBuilder
    * <code>.google.spanner.v1.ResultSetStats stats = 5;</code>
    */
   com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 8 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSet.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSet.java
index 6140bf77e6e..9def6101bbc 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSet.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSet.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/result_set.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 /**
@@ -276,6 +276,75 @@ public com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder() {
     return stats_ == null ? com.google.spanner.v1.ResultSetStats.getDefaultInstance() : stats_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 5;
+  private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return ((bitField0_ & 0x00000004) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -299,6 +368,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000002) != 0)) {
       output.writeMessage(3, getStats());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      output.writeMessage(5, getPrecommitToken());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -317,6 +389,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000002) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getStats());
     }
+    if (((bitField0_ & 0x00000004) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(5, getPrecommitToken());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -341,6 +416,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasStats()) {
       if (!getStats().equals(other.getStats())) return false;
     }
+    if (hasPrecommitToken() != other.hasPrecommitToken()) return false;
+    if (hasPrecommitToken()) {
+      if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -364,6 +443,10 @@ public int hashCode() {
       hash = (37 * hash) + STATS_FIELD_NUMBER;
       hash = (53 * hash) + getStats().hashCode();
     }
+    if (hasPrecommitToken()) {
+      hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+      hash = (53 * hash) + getPrecommitToken().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -506,6 +589,7 @@ private void maybeForceBuilderInitialization() {
         getMetadataFieldBuilder();
         getRowsFieldBuilder();
         getStatsFieldBuilder();
+        getPrecommitTokenFieldBuilder();
       }
     }
 
@@ -530,6 +614,11 @@ public Builder clear() {
         statsBuilder_.dispose();
         statsBuilder_ = null;
       }
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
       return this;
     }
 
@@ -587,6 +676,11 @@ private void buildPartial0(com.google.spanner.v1.ResultSet result) {
         result.stats_ = statsBuilder_ == null ? stats_ : statsBuilder_.build();
         to_bitField0_ |= 0x00000002;
       }
+      if (((from_bitField0_ & 0x00000008) != 0)) {
+        result.precommitToken_ =
+            precommitTokenBuilder_ == null ? precommitToken_ : precommitTokenBuilder_.build();
+        to_bitField0_ |= 0x00000004;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -668,6 +762,9 @@ public Builder mergeFrom(com.google.spanner.v1.ResultSet other) {
       if (other.hasStats()) {
         mergeStats(other.getStats());
       }
+      if (other.hasPrecommitToken()) {
+        mergePrecommitToken(other.getPrecommitToken());
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -718,6 +815,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000004;
                 break;
               } // case 26
+            case 42:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000008;
+                break;
+              } // case 42
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -1598,6 +1701,250 @@ public com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder() {
       return statsBuilder_;
     }
 
+    private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    public boolean hasPrecommitToken() {
+      return ((bitField0_ & 0x00000008) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The precommitToken.
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      } else {
+        return precommitTokenBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        precommitToken_ = value;
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        precommitToken_ = builderForValue.build();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (((bitField0_ & 0x00000008) != 0)
+            && precommitToken_ != null
+            && precommitToken_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          getPrecommitTokenBuilder().mergeFrom(value);
+        } else {
+          precommitToken_ = value;
+        }
+      } else {
+        precommitTokenBuilder_.mergeFrom(value);
+      }
+      if (precommitToken_ != null) {
+        bitField0_ |= 0x00000008;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000008);
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      bitField0_ |= 0x00000008;
+      onChanged();
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if (precommitTokenBuilder_ != null) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included if the read-write transaction
+     * is on a multiplexed session.
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the
+     * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+     * </pre>
+     *
+     * <code>
+     * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                getPrecommitToken(), getParentForChildren(), isClean());
+        precommitToken_ = null;
+      }
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetOrBuilder.java
index 3342ed60322..7d8601247cd 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetOrBuilder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/result_set.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 public interface ResultSetOrBuilder
@@ -190,4 +190,57 @@ public interface ResultSetOrBuilder
    * <code>.google.spanner.v1.ResultSetStats stats = 3;</code>
    */
   com.google.spanner.v1.ResultSetStatsOrBuilder getStatsOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included if the read-write transaction
+   * is on a multiplexed session.
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the
+   * [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+   * </pre>
+   *
+   * <code>
+   * .google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 5 [(.google.api.field_behavior) = OPTIONAL];
+   * </code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetProto.java
index cab0e9c2c0d..a45bb97cd5f 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ResultSetProto.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/result_set.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 public final class ResultSetProto {
@@ -55,39 +55,45 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     java.lang.String[] descriptorData = {
       "\n\"google/spanner/v1/result_set.proto\022\021go"
           + "ogle.spanner.v1\032\034google/protobuf/struct."
-          + "proto\032\"google/spanner/v1/query_plan.prot"
-          + "o\032#google/spanner/v1/transaction.proto\032\034"
-          + "google/spanner/v1/type.proto\"\237\001\n\tResultS"
-          + "et\0226\n\010metadata\030\001 \001(\0132$.google.spanner.v1"
-          + ".ResultSetMetadata\022(\n\004rows\030\002 \003(\0132\032.googl"
-          + "e.protobuf.ListValue\0220\n\005stats\030\003 \001(\0132!.go"
-          + "ogle.spanner.v1.ResultSetStats\"\321\001\n\020Parti"
-          + "alResultSet\0226\n\010metadata\030\001 \001(\0132$.google.s"
-          + "panner.v1.ResultSetMetadata\022&\n\006values\030\002 "
-          + "\003(\0132\026.google.protobuf.Value\022\025\n\rchunked_v"
-          + "alue\030\003 \001(\010\022\024\n\014resume_token\030\004 \001(\014\0220\n\005stat"
-          + "s\030\005 \001(\0132!.google.spanner.v1.ResultSetSta"
-          + "ts\"\267\001\n\021ResultSetMetadata\022/\n\010row_type\030\001 \001"
-          + "(\0132\035.google.spanner.v1.StructType\0223\n\013tra"
-          + "nsaction\030\002 \001(\0132\036.google.spanner.v1.Trans"
-          + "action\022<\n\025undeclared_parameters\030\003 \001(\0132\035."
-          + "google.spanner.v1.StructType\"\271\001\n\016ResultS"
-          + "etStats\0220\n\nquery_plan\030\001 \001(\0132\034.google.spa"
-          + "nner.v1.QueryPlan\022,\n\013query_stats\030\002 \001(\0132\027"
-          + ".google.protobuf.Struct\022\031\n\017row_count_exa"
-          + "ct\030\003 \001(\003H\000\022\037\n\025row_count_lower_bound\030\004 \001("
-          + "\003H\000B\013\n\trow_countB\264\001\n\025com.google.spanner."
-          + "v1B\016ResultSetProtoP\001Z5cloud.google.com/g"
-          + "o/spanner/apiv1/spannerpb;spannerpb\370\001\001\252\002"
-          + "\027Google.Cloud.Spanner.V1\312\002\027Google\\Cloud\\"
-          + "Spanner\\V1\352\002\032Google::Cloud::Spanner::V1b"
-          + "\006proto3"
+          + "proto\032\037google/api/field_behavior.proto\032\""
+          + "google/spanner/v1/query_plan.proto\032#goog"
+          + "le/spanner/v1/transaction.proto\032\034google/"
+          + "spanner/v1/type.proto\"\362\001\n\tResultSet\0226\n\010m"
+          + "etadata\030\001 \001(\0132$.google.spanner.v1.Result"
+          + "SetMetadata\022(\n\004rows\030\002 \003(\0132\032.google.proto"
+          + "buf.ListValue\0220\n\005stats\030\003 \001(\0132!.google.sp"
+          + "anner.v1.ResultSetStats\022Q\n\017precommit_tok"
+          + "en\030\005 \001(\01323.google.spanner.v1.Multiplexed"
+          + "SessionPrecommitTokenB\003\340A\001\"\244\002\n\020PartialRe"
+          + "sultSet\0226\n\010metadata\030\001 \001(\0132$.google.spann"
+          + "er.v1.ResultSetMetadata\022&\n\006values\030\002 \003(\0132"
+          + "\026.google.protobuf.Value\022\025\n\rchunked_value"
+          + "\030\003 \001(\010\022\024\n\014resume_token\030\004 \001(\014\0220\n\005stats\030\005 "
+          + "\001(\0132!.google.spanner.v1.ResultSetStats\022Q"
+          + "\n\017precommit_token\030\010 \001(\01323.google.spanner"
+          + ".v1.MultiplexedSessionPrecommitTokenB\003\340A"
+          + "\001\"\267\001\n\021ResultSetMetadata\022/\n\010row_type\030\001 \001("
+          + "\0132\035.google.spanner.v1.StructType\0223\n\013tran"
+          + "saction\030\002 \001(\0132\036.google.spanner.v1.Transa"
+          + "ction\022<\n\025undeclared_parameters\030\003 \001(\0132\035.g"
+          + "oogle.spanner.v1.StructType\"\271\001\n\016ResultSe"
+          + "tStats\0220\n\nquery_plan\030\001 \001(\0132\034.google.span"
+          + "ner.v1.QueryPlan\022,\n\013query_stats\030\002 \001(\0132\027."
+          + "google.protobuf.Struct\022\031\n\017row_count_exac"
+          + "t\030\003 \001(\003H\000\022\037\n\025row_count_lower_bound\030\004 \001(\003"
+          + "H\000B\013\n\trow_countB\264\001\n\025com.google.spanner.v"
+          + "1B\016ResultSetProtoP\001Z5cloud.google.com/go"
+          + "/spanner/apiv1/spannerpb;spannerpb\370\001\001\252\002\027"
+          + "Google.Cloud.Spanner.V1\312\002\027Google\\Cloud\\S"
+          + "panner\\V1\352\002\032Google::Cloud::Spanner::V1b\006"
+          + "proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
             descriptorData,
             new com.google.protobuf.Descriptors.FileDescriptor[] {
               com.google.protobuf.StructProto.getDescriptor(),
+              com.google.api.FieldBehaviorProto.getDescriptor(),
               com.google.spanner.v1.QueryPlanProto.getDescriptor(),
               com.google.spanner.v1.TransactionProto.getDescriptor(),
               com.google.spanner.v1.TypeProto.getDescriptor(),
@@ -98,7 +104,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_ResultSet_descriptor,
             new java.lang.String[] {
-              "Metadata", "Rows", "Stats",
+              "Metadata", "Rows", "Stats", "PrecommitToken",
             });
     internal_static_google_spanner_v1_PartialResultSet_descriptor =
         getDescriptor().getMessageTypes().get(1);
@@ -106,7 +112,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_PartialResultSet_descriptor,
             new java.lang.String[] {
-              "Metadata", "Values", "ChunkedValue", "ResumeToken", "Stats",
+              "Metadata", "Values", "ChunkedValue", "ResumeToken", "Stats", "PrecommitToken",
             });
     internal_static_google_spanner_v1_ResultSetMetadata_descriptor =
         getDescriptor().getMessageTypes().get(2);
@@ -124,7 +130,13 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
             new java.lang.String[] {
               "QueryPlan", "QueryStats", "RowCountExact", "RowCountLowerBound", "RowCount",
             });
+    com.google.protobuf.ExtensionRegistry registry =
+        com.google.protobuf.ExtensionRegistry.newInstance();
+    registry.add(com.google.api.FieldBehaviorProto.fieldBehavior);
+    com.google.protobuf.Descriptors.FileDescriptor.internalUpdateFileDescriptor(
+        descriptor, registry);
     com.google.protobuf.StructProto.getDescriptor();
+    com.google.api.FieldBehaviorProto.getDescriptor();
     com.google.spanner.v1.QueryPlanProto.getDescriptor();
     com.google.spanner.v1.TransactionProto.getDescriptor();
     com.google.spanner.v1.TypeProto.getDescriptor();
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
index a2b7ea2625e..0badef8d708 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/spanner.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 public final class SpannerProto {
@@ -271,167 +271,172 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "(\0132C.google.spanner.v1.ExecuteBatchDmlRe"
           + "quest.Statement.ParamTypesEntry\032J\n\017Param"
           + "TypesEntry\022\013\n\003key\030\001 \001(\t\022&\n\005value\030\002 \001(\0132\027"
-          + ".google.spanner.v1.Type:\0028\001\"p\n\027ExecuteBa"
-          + "tchDmlResponse\0221\n\013result_sets\030\001 \003(\0132\034.go"
-          + "ogle.spanner.v1.ResultSet\022\"\n\006status\030\002 \001("
-          + "\0132\022.google.rpc.Status\"H\n\020PartitionOption"
-          + "s\022\034\n\024partition_size_bytes\030\001 \001(\003\022\026\n\016max_p"
-          + "artitions\030\002 \001(\003\"\243\003\n\025PartitionQueryReques"
-          + "t\0227\n\007session\030\001 \001(\tB&\340A\002\372A \n\036spanner.goog"
-          + "leapis.com/Session\022;\n\013transaction\030\002 \001(\0132"
-          + "&.google.spanner.v1.TransactionSelector\022"
-          + "\020\n\003sql\030\003 \001(\tB\003\340A\002\022\'\n\006params\030\004 \001(\0132\027.goog"
-          + "le.protobuf.Struct\022M\n\013param_types\030\005 \003(\0132"
-          + "8.google.spanner.v1.PartitionQueryReques"
-          + "t.ParamTypesEntry\022>\n\021partition_options\030\006"
-          + " \001(\0132#.google.spanner.v1.PartitionOption"
-          + "s\032J\n\017ParamTypesEntry\022\013\n\003key\030\001 \001(\t\022&\n\005val"
-          + "ue\030\002 \001(\0132\027.google.spanner.v1.Type:\0028\001\"\261\002"
-          + "\n\024PartitionReadRequest\0227\n\007session\030\001 \001(\tB"
-          + "&\340A\002\372A \n\036spanner.googleapis.com/Session\022"
-          + ";\n\013transaction\030\002 \001(\0132&.google.spanner.v1"
-          + ".TransactionSelector\022\022\n\005table\030\003 \001(\tB\003\340A\002"
-          + "\022\r\n\005index\030\004 \001(\t\022\017\n\007columns\030\005 \003(\t\022/\n\007key_"
-          + "set\030\006 \001(\0132\031.google.spanner.v1.KeySetB\003\340A"
-          + "\002\022>\n\021partition_options\030\t \001(\0132#.google.sp"
-          + "anner.v1.PartitionOptions\"$\n\tPartition\022\027"
-          + "\n\017partition_token\030\001 \001(\014\"z\n\021PartitionResp"
-          + "onse\0220\n\npartitions\030\001 \003(\0132\034.google.spanne"
-          + "r.v1.Partition\0223\n\013transaction\030\002 \001(\0132\036.go"
-          + "ogle.spanner.v1.Transaction\"\366\005\n\013ReadRequ"
-          + "est\0227\n\007session\030\001 \001(\tB&\340A\002\372A \n\036spanner.go"
-          + "ogleapis.com/Session\022;\n\013transaction\030\002 \001("
-          + "\0132&.google.spanner.v1.TransactionSelecto"
-          + "r\022\022\n\005table\030\003 \001(\tB\003\340A\002\022\r\n\005index\030\004 \001(\t\022\024\n\007"
-          + "columns\030\005 \003(\tB\003\340A\002\022/\n\007key_set\030\006 \001(\0132\031.go"
-          + "ogle.spanner.v1.KeySetB\003\340A\002\022\r\n\005limit\030\010 \001"
-          + "(\003\022\024\n\014resume_token\030\t \001(\014\022\027\n\017partition_to"
-          + "ken\030\n \001(\014\022:\n\017request_options\030\013 \001(\0132!.goo"
-          + "gle.spanner.v1.RequestOptions\022E\n\025directe"
-          + "d_read_options\030\016 \001(\0132&.google.spanner.v1"
-          + ".DirectedReadOptions\022\032\n\022data_boost_enabl"
-          + "ed\030\017 \001(\010\022=\n\010order_by\030\020 \001(\0162&.google.span"
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+          + "/auth/spanner.dataB\221\002\n\025com.google.spanne"
+          + "r.v1B\014SpannerProtoP\001Z5cloud.google.com/g"
+          + "o/spanner/apiv1/spannerpb;spannerpb\252\002\027Go"
+          + "ogle.Cloud.Spanner.V1\312\002\027Google\\Cloud\\Spa"
+          + "nner\\V1\352\002\032Google::Cloud::Spanner::V1\352A_\n"
+          + "\037spanner.googleapis.com/Database\022<projec"
+          + "ts/{project}/instances/{instance}/databa"
+          + "ses/{database}P\000b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -637,7 +642,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_ExecuteBatchDmlResponse_descriptor,
             new java.lang.String[] {
-              "ResultSets", "Status",
+              "ResultSets", "Status", "PrecommitToken",
             });
     internal_static_google_spanner_v1_PartitionOptions_descriptor =
         getDescriptor().getMessageTypes().get(13);
@@ -714,7 +719,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_BeginTransactionRequest_descriptor,
             new java.lang.String[] {
-              "Session", "Options", "RequestOptions",
+              "Session", "Options", "RequestOptions", "MutationKey",
             });
     internal_static_google_spanner_v1_CommitRequest_descriptor =
         getDescriptor().getMessageTypes().get(20);
@@ -729,6 +734,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
               "ReturnCommitStats",
               "MaxCommitDelay",
               "RequestOptions",
+              "PrecommitToken",
               "Transaction",
             });
     internal_static_google_spanner_v1_RollbackRequest_descriptor =
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Transaction.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Transaction.java
index 7d12fa22d15..3a31c4b50c9 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Transaction.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Transaction.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/transaction.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 /**
@@ -154,6 +154,75 @@ public com.google.protobuf.TimestampOrBuilder getReadTimestampOrBuilder() {
         : readTimestamp_;
   }
 
+  public static final int PRECOMMIT_TOKEN_FIELD_NUMBER = 3;
+  private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  @java.lang.Override
+  public boolean hasPrecommitToken() {
+    return ((bitField0_ & 0x00000002) != 0);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   *
+   * @return The precommitToken.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+      getPrecommitTokenOrBuilder() {
+    return precommitToken_ == null
+        ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+        : precommitToken_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -174,6 +243,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000001) != 0)) {
       output.writeMessage(2, getReadTimestamp());
     }
+    if (((bitField0_ & 0x00000002) != 0)) {
+      output.writeMessage(3, getPrecommitToken());
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -189,6 +261,9 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000001) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, getReadTimestamp());
     }
+    if (((bitField0_ & 0x00000002) != 0)) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getPrecommitToken());
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -209,6 +284,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasReadTimestamp()) {
       if (!getReadTimestamp().equals(other.getReadTimestamp())) return false;
     }
+    if (hasPrecommitToken() != other.hasPrecommitToken()) return false;
+    if (hasPrecommitToken()) {
+      if (!getPrecommitToken().equals(other.getPrecommitToken())) return false;
+    }
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -226,6 +305,10 @@ public int hashCode() {
       hash = (37 * hash) + READ_TIMESTAMP_FIELD_NUMBER;
       hash = (53 * hash) + getReadTimestamp().hashCode();
     }
+    if (hasPrecommitToken()) {
+      hash = (37 * hash) + PRECOMMIT_TOKEN_FIELD_NUMBER;
+      hash = (53 * hash) + getPrecommitToken().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -366,6 +449,7 @@ private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
     private void maybeForceBuilderInitialization() {
       if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
         getReadTimestampFieldBuilder();
+        getPrecommitTokenFieldBuilder();
       }
     }
 
@@ -379,6 +463,11 @@ public Builder clear() {
         readTimestampBuilder_.dispose();
         readTimestampBuilder_ = null;
       }
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
       return this;
     }
 
@@ -423,6 +512,11 @@ private void buildPartial0(com.google.spanner.v1.Transaction result) {
             readTimestampBuilder_ == null ? readTimestamp_ : readTimestampBuilder_.build();
         to_bitField0_ |= 0x00000001;
       }
+      if (((from_bitField0_ & 0x00000004) != 0)) {
+        result.precommitToken_ =
+            precommitTokenBuilder_ == null ? precommitToken_ : precommitTokenBuilder_.build();
+        to_bitField0_ |= 0x00000002;
+      }
       result.bitField0_ |= to_bitField0_;
     }
 
@@ -477,6 +571,9 @@ public Builder mergeFrom(com.google.spanner.v1.Transaction other) {
       if (other.hasReadTimestamp()) {
         mergeReadTimestamp(other.getReadTimestamp());
       }
+      if (other.hasPrecommitToken()) {
+        mergePrecommitToken(other.getPrecommitToken());
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -515,6 +612,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000002;
                 break;
               } // case 18
+            case 26:
+              {
+                input.readMessage(getPrecommitTokenFieldBuilder().getBuilder(), extensionRegistry);
+                bitField0_ |= 0x00000004;
+                break;
+              } // case 26
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -840,6 +943,250 @@ public com.google.protobuf.TimestampOrBuilder getReadTimestampOrBuilder() {
       return readTimestampBuilder_;
     }
 
+    private com.google.spanner.v1.MultiplexedSessionPrecommitToken precommitToken_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        precommitTokenBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     *
+     * @return Whether the precommitToken field is set.
+     */
+    public boolean hasPrecommitToken() {
+      return ((bitField0_ & 0x00000004) != 0);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     *
+     * @return The precommitToken.
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken() {
+      if (precommitTokenBuilder_ == null) {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      } else {
+        return precommitTokenBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public Builder setPrecommitToken(com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        precommitToken_ = value;
+      } else {
+        precommitTokenBuilder_.setMessage(value);
+      }
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public Builder setPrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder builderForValue) {
+      if (precommitTokenBuilder_ == null) {
+        precommitToken_ = builderForValue.build();
+      } else {
+        precommitTokenBuilder_.setMessage(builderForValue.build());
+      }
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public Builder mergePrecommitToken(
+        com.google.spanner.v1.MultiplexedSessionPrecommitToken value) {
+      if (precommitTokenBuilder_ == null) {
+        if (((bitField0_ & 0x00000004) != 0)
+            && precommitToken_ != null
+            && precommitToken_
+                != com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()) {
+          getPrecommitTokenBuilder().mergeFrom(value);
+        } else {
+          precommitToken_ = value;
+        }
+      } else {
+        precommitTokenBuilder_.mergeFrom(value);
+      }
+      if (precommitToken_ != null) {
+        bitField0_ |= 0x00000004;
+        onChanged();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public Builder clearPrecommitToken() {
+      bitField0_ = (bitField0_ & ~0x00000004);
+      precommitToken_ = null;
+      if (precommitTokenBuilder_ != null) {
+        precommitTokenBuilder_.dispose();
+        precommitTokenBuilder_ = null;
+      }
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder
+        getPrecommitTokenBuilder() {
+      bitField0_ |= 0x00000004;
+      onChanged();
+      return getPrecommitTokenFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    public com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder
+        getPrecommitTokenOrBuilder() {
+      if (precommitTokenBuilder_ != null) {
+        return precommitTokenBuilder_.getMessageOrBuilder();
+      } else {
+        return precommitToken_ == null
+            ? com.google.spanner.v1.MultiplexedSessionPrecommitToken.getDefaultInstance()
+            : precommitToken_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A precommit token will be included in the response of a BeginTransaction
+     * request if the read-write transaction is on a multiplexed session and
+     * a mutation_key was specified in the
+     * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+     * The precommit token with the highest sequence number from this transaction
+     * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+     * request for this transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+            com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+            com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>
+        getPrecommitTokenFieldBuilder() {
+      if (precommitTokenBuilder_ == null) {
+        precommitTokenBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken,
+                com.google.spanner.v1.MultiplexedSessionPrecommitToken.Builder,
+                com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder>(
+                getPrecommitToken(), getParentForChildren(), isClean());
+        precommitToken_ = null;
+      }
+      return precommitTokenBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
index 60b3cdcc14a..f2acb127463 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/transaction.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 /**
@@ -413,6 +413,23 @@ public interface ReadWriteOrBuilder
      * @return The readLockMode.
      */
     com.google.spanner.v1.TransactionOptions.ReadWrite.ReadLockMode getReadLockMode();
+
+    /**
+     *
+     *
+     * <pre>
+     * Clients should pass the transaction ID of the previous transaction
+     * attempt that was aborted if this transaction is being executed on a
+     * multiplexed session.
+     * </pre>
+     *
+     * <code>
+     * bytes multiplexed_session_previous_transaction_id = 2 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The multiplexedSessionPreviousTransactionId.
+     */
+    com.google.protobuf.ByteString getMultiplexedSessionPreviousTransactionId();
   }
   /**
    *
@@ -436,6 +453,7 @@ private ReadWrite(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
 
     private ReadWrite() {
       readLockMode_ = 0;
+      multiplexedSessionPreviousTransactionId_ = com.google.protobuf.ByteString.EMPTY;
     }
 
     @java.lang.Override
@@ -672,6 +690,29 @@ public com.google.spanner.v1.TransactionOptions.ReadWrite.ReadLockMode getReadLo
           : result;
     }
 
+    public static final int MULTIPLEXED_SESSION_PREVIOUS_TRANSACTION_ID_FIELD_NUMBER = 2;
+    private com.google.protobuf.ByteString multiplexedSessionPreviousTransactionId_ =
+        com.google.protobuf.ByteString.EMPTY;
+    /**
+     *
+     *
+     * <pre>
+     * Clients should pass the transaction ID of the previous transaction
+     * attempt that was aborted if this transaction is being executed on a
+     * multiplexed session.
+     * </pre>
+     *
+     * <code>
+     * bytes multiplexed_session_previous_transaction_id = 2 [(.google.api.field_behavior) = OPTIONAL];
+     * </code>
+     *
+     * @return The multiplexedSessionPreviousTransactionId.
+     */
+    @java.lang.Override
+    public com.google.protobuf.ByteString getMultiplexedSessionPreviousTransactionId() {
+      return multiplexedSessionPreviousTransactionId_;
+    }
+
     private byte memoizedIsInitialized = -1;
 
     @java.lang.Override
@@ -692,6 +733,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
               .getNumber()) {
         output.writeEnum(1, readLockMode_);
       }
+      if (!multiplexedSessionPreviousTransactionId_.isEmpty()) {
+        output.writeBytes(2, multiplexedSessionPreviousTransactionId_);
+      }
       getUnknownFields().writeTo(output);
     }
 
@@ -707,6 +751,11 @@ public int getSerializedSize() {
               .getNumber()) {
         size += com.google.protobuf.CodedOutputStream.computeEnumSize(1, readLockMode_);
       }
+      if (!multiplexedSessionPreviousTransactionId_.isEmpty()) {
+        size +=
+            com.google.protobuf.CodedOutputStream.computeBytesSize(
+                2, multiplexedSessionPreviousTransactionId_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSize = size;
       return size;
@@ -724,6 +773,8 @@ public boolean equals(final java.lang.Object obj) {
           (com.google.spanner.v1.TransactionOptions.ReadWrite) obj;
 
       if (readLockMode_ != other.readLockMode_) return false;
+      if (!getMultiplexedSessionPreviousTransactionId()
+          .equals(other.getMultiplexedSessionPreviousTransactionId())) return false;
       if (!getUnknownFields().equals(other.getUnknownFields())) return false;
       return true;
     }
@@ -737,6 +788,8 @@ public int hashCode() {
       hash = (19 * hash) + getDescriptor().hashCode();
       hash = (37 * hash) + READ_LOCK_MODE_FIELD_NUMBER;
       hash = (53 * hash) + readLockMode_;
+      hash = (37 * hash) + MULTIPLEXED_SESSION_PREVIOUS_TRANSACTION_ID_FIELD_NUMBER;
+      hash = (53 * hash) + getMultiplexedSessionPreviousTransactionId().hashCode();
       hash = (29 * hash) + getUnknownFields().hashCode();
       memoizedHashCode = hash;
       return hash;
@@ -880,6 +933,7 @@ public Builder clear() {
         super.clear();
         bitField0_ = 0;
         readLockMode_ = 0;
+        multiplexedSessionPreviousTransactionId_ = com.google.protobuf.ByteString.EMPTY;
         return this;
       }
 
@@ -919,6 +973,10 @@ private void buildPartial0(com.google.spanner.v1.TransactionOptions.ReadWrite re
         if (((from_bitField0_ & 0x00000001) != 0)) {
           result.readLockMode_ = readLockMode_;
         }
+        if (((from_bitField0_ & 0x00000002) != 0)) {
+          result.multiplexedSessionPreviousTransactionId_ =
+              multiplexedSessionPreviousTransactionId_;
+        }
       }
 
       @java.lang.Override
@@ -972,6 +1030,11 @@ public Builder mergeFrom(com.google.spanner.v1.TransactionOptions.ReadWrite othe
         if (other.readLockMode_ != 0) {
           setReadLockModeValue(other.getReadLockModeValue());
         }
+        if (other.getMultiplexedSessionPreviousTransactionId()
+            != com.google.protobuf.ByteString.EMPTY) {
+          setMultiplexedSessionPreviousTransactionId(
+              other.getMultiplexedSessionPreviousTransactionId());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         onChanged();
         return this;
@@ -1004,6 +1067,12 @@ public Builder mergeFrom(
                   bitField0_ |= 0x00000001;
                   break;
                 } // case 8
+              case 18:
+                {
+                  multiplexedSessionPreviousTransactionId_ = input.readBytes();
+                  bitField0_ |= 0x00000002;
+                  break;
+                } // case 18
               default:
                 {
                   if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -1122,6 +1191,76 @@ public Builder clearReadLockMode() {
         return this;
       }
 
+      private com.google.protobuf.ByteString multiplexedSessionPreviousTransactionId_ =
+          com.google.protobuf.ByteString.EMPTY;
+      /**
+       *
+       *
+       * <pre>
+       * Clients should pass the transaction ID of the previous transaction
+       * attempt that was aborted if this transaction is being executed on a
+       * multiplexed session.
+       * </pre>
+       *
+       * <code>
+       * bytes multiplexed_session_previous_transaction_id = 2 [(.google.api.field_behavior) = OPTIONAL];
+       * </code>
+       *
+       * @return The multiplexedSessionPreviousTransactionId.
+       */
+      @java.lang.Override
+      public com.google.protobuf.ByteString getMultiplexedSessionPreviousTransactionId() {
+        return multiplexedSessionPreviousTransactionId_;
+      }
+      /**
+       *
+       *
+       * <pre>
+       * Clients should pass the transaction ID of the previous transaction
+       * attempt that was aborted if this transaction is being executed on a
+       * multiplexed session.
+       * </pre>
+       *
+       * <code>
+       * bytes multiplexed_session_previous_transaction_id = 2 [(.google.api.field_behavior) = OPTIONAL];
+       * </code>
+       *
+       * @param value The multiplexedSessionPreviousTransactionId to set.
+       * @return This builder for chaining.
+       */
+      public Builder setMultiplexedSessionPreviousTransactionId(
+          com.google.protobuf.ByteString value) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        multiplexedSessionPreviousTransactionId_ = value;
+        bitField0_ |= 0x00000002;
+        onChanged();
+        return this;
+      }
+      /**
+       *
+       *
+       * <pre>
+       * Clients should pass the transaction ID of the previous transaction
+       * attempt that was aborted if this transaction is being executed on a
+       * multiplexed session.
+       * </pre>
+       *
+       * <code>
+       * bytes multiplexed_session_previous_transaction_id = 2 [(.google.api.field_behavior) = OPTIONAL];
+       * </code>
+       *
+       * @return This builder for chaining.
+       */
+      public Builder clearMultiplexedSessionPreviousTransactionId() {
+        bitField0_ = (bitField0_ & ~0x00000002);
+        multiplexedSessionPreviousTransactionId_ =
+            getDefaultInstance().getMultiplexedSessionPreviousTransactionId();
+        onChanged();
+        return this;
+      }
+
       @java.lang.Override
       public final Builder setUnknownFields(
           final com.google.protobuf.UnknownFieldSet unknownFields) {
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOrBuilder.java
index 621c88aa4ca..5208eda515b 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOrBuilder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/transaction.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 public interface TransactionOrBuilder
@@ -93,4 +93,57 @@ public interface TransactionOrBuilder
    * <code>.google.protobuf.Timestamp read_timestamp = 2;</code>
    */
   com.google.protobuf.TimestampOrBuilder getReadTimestampOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   *
+   * @return Whether the precommitToken field is set.
+   */
+  boolean hasPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   *
+   * @return The precommitToken.
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitToken getPrecommitToken();
+  /**
+   *
+   *
+   * <pre>
+   * A precommit token will be included in the response of a BeginTransaction
+   * request if the read-write transaction is on a multiplexed session and
+   * a mutation_key was specified in the
+   * [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+   * The precommit token with the highest sequence number from this transaction
+   * attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+   * request for this transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.MultiplexedSessionPrecommitToken precommit_token = 3;</code>
+   */
+  com.google.spanner.v1.MultiplexedSessionPrecommitTokenOrBuilder getPrecommitTokenOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
index 6c0a92fbd65..a6b036013e5 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Google LLC
+ * Copyright 2023 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/spanner/v1/transaction.proto
 
-// Protobuf Java Version: 3.25.4
+// Protobuf Java Version: 3.25.3
 package com.google.spanner.v1;
 
 public final class TransactionProto {
@@ -52,6 +52,10 @@ public static void registerAllExtensions(com.google.protobuf.ExtensionRegistry r
       internal_static_google_spanner_v1_TransactionSelector_descriptor;
   static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
       internal_static_google_spanner_v1_TransactionSelector_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+      internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor;
+  static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     return descriptor;
@@ -64,37 +68,43 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
       "\n#google/spanner/v1/transaction.proto\022\021g"
           + "oogle.spanner.v1\032\036google/protobuf/durati"
           + "on.proto\032\037google/protobuf/timestamp.prot"
-          + "o\"\224\006\n\022TransactionOptions\022E\n\nread_write\030\001"
-          + " \001(\0132/.google.spanner.v1.TransactionOpti"
-          + "ons.ReadWriteH\000\022O\n\017partitioned_dml\030\003 \001(\013"
-          + "24.google.spanner.v1.TransactionOptions."
-          + "PartitionedDmlH\000\022C\n\tread_only\030\002 \001(\0132..go"
-          + "ogle.spanner.v1.TransactionOptions.ReadO"
-          + "nlyH\000\022\'\n\037exclude_txn_from_change_streams"
-          + "\030\005 \001(\010\032\262\001\n\tReadWrite\022T\n\016read_lock_mode\030\001"
-          + " \001(\0162<.google.spanner.v1.TransactionOpti"
-          + "ons.ReadWrite.ReadLockMode\"O\n\014ReadLockMo"
-          + "de\022\036\n\032READ_LOCK_MODE_UNSPECIFIED\020\000\022\017\n\013PE"
-          + "SSIMISTIC\020\001\022\016\n\nOPTIMISTIC\020\002\032\020\n\016Partition"
-          + "edDml\032\250\002\n\010ReadOnly\022\020\n\006strong\030\001 \001(\010H\000\0228\n\022"
-          + "min_read_timestamp\030\002 \001(\0132\032.google.protob"
-          + "uf.TimestampH\000\0222\n\rmax_staleness\030\003 \001(\0132\031."
-          + "google.protobuf.DurationH\000\0224\n\016read_times"
-          + "tamp\030\004 \001(\0132\032.google.protobuf.TimestampH\000"
-          + "\0224\n\017exact_staleness\030\005 \001(\0132\031.google.proto"
-          + "buf.DurationH\000\022\035\n\025return_read_timestamp\030"
-          + "\006 \001(\010B\021\n\017timestamp_boundB\006\n\004mode\"M\n\013Tran"
-          + "saction\022\n\n\002id\030\001 \001(\014\0222\n\016read_timestamp\030\002 "
-          + "\001(\0132\032.google.protobuf.Timestamp\"\244\001\n\023Tran"
-          + "sactionSelector\022;\n\nsingle_use\030\001 \001(\0132%.go"
-          + "ogle.spanner.v1.TransactionOptionsH\000\022\014\n\002"
-          + "id\030\002 \001(\014H\000\0226\n\005begin\030\003 \001(\0132%.google.spann"
-          + "er.v1.TransactionOptionsH\000B\n\n\010selectorB\263"
-          + "\001\n\025com.google.spanner.v1B\020TransactionPro"
-          + "toP\001Z5cloud.google.com/go/spanner/apiv1/"
-          + "spannerpb;spannerpb\252\002\027Google.Cloud.Spann"
-          + "er.V1\312\002\027Google\\Cloud\\Spanner\\V1\352\002\032Google"
-          + "::Cloud::Spanner::V1b\006proto3"
+          + "o\032\037google/api/field_behavior.proto\"\316\006\n\022T"
+          + "ransactionOptions\022E\n\nread_write\030\001 \001(\0132/."
+          + "google.spanner.v1.TransactionOptions.Rea"
+          + "dWriteH\000\022O\n\017partitioned_dml\030\003 \001(\01324.goog"
+          + "le.spanner.v1.TransactionOptions.Partiti"
+          + "onedDmlH\000\022C\n\tread_only\030\002 \001(\0132..google.sp"
+          + "anner.v1.TransactionOptions.ReadOnlyH\000\022\'"
+          + "\n\037exclude_txn_from_change_streams\030\005 \001(\010\032"
+          + "\354\001\n\tReadWrite\022T\n\016read_lock_mode\030\001 \001(\0162<."
+          + "google.spanner.v1.TransactionOptions.Rea"
+          + "dWrite.ReadLockMode\0228\n+multiplexed_sessi"
+          + "on_previous_transaction_id\030\002 \001(\014B\003\340A\001\"O\n"
+          + "\014ReadLockMode\022\036\n\032READ_LOCK_MODE_UNSPECIF"
+          + "IED\020\000\022\017\n\013PESSIMISTIC\020\001\022\016\n\nOPTIMISTIC\020\002\032\020"
+          + "\n\016PartitionedDml\032\250\002\n\010ReadOnly\022\020\n\006strong\030"
+          + "\001 \001(\010H\000\0228\n\022min_read_timestamp\030\002 \001(\0132\032.go"
+          + "ogle.protobuf.TimestampH\000\0222\n\rmax_stalene"
+          + "ss\030\003 \001(\0132\031.google.protobuf.DurationH\000\0224\n"
+          + "\016read_timestamp\030\004 \001(\0132\032.google.protobuf."
+          + "TimestampH\000\0224\n\017exact_staleness\030\005 \001(\0132\031.g"
+          + "oogle.protobuf.DurationH\000\022\035\n\025return_read"
+          + "_timestamp\030\006 \001(\010B\021\n\017timestamp_boundB\006\n\004m"
+          + "ode\"\233\001\n\013Transaction\022\n\n\002id\030\001 \001(\014\0222\n\016read_"
+          + "timestamp\030\002 \001(\0132\032.google.protobuf.Timest"
+          + "amp\022L\n\017precommit_token\030\003 \001(\01323.google.sp"
+          + "anner.v1.MultiplexedSessionPrecommitToke"
+          + "n\"\244\001\n\023TransactionSelector\022;\n\nsingle_use\030"
+          + "\001 \001(\0132%.google.spanner.v1.TransactionOpt"
+          + "ionsH\000\022\014\n\002id\030\002 \001(\014H\000\0226\n\005begin\030\003 \001(\0132%.go"
+          + "ogle.spanner.v1.TransactionOptionsH\000B\n\n\010"
+          + "selector\"L\n MultiplexedSessionPrecommitT"
+          + "oken\022\027\n\017precommit_token\030\001 \001(\014\022\017\n\007seq_num"
+          + "\030\002 \001(\005B\263\001\n\025com.google.spanner.v1B\020Transa"
+          + "ctionProtoP\001Z5cloud.google.com/go/spanne"
+          + "r/apiv1/spannerpb;spannerpb\252\002\027Google.Clo"
+          + "ud.Spanner.V1\312\002\027Google\\Cloud\\Spanner\\V1\352"
+          + "\002\032Google::Cloud::Spanner::V1b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -102,6 +112,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
             new com.google.protobuf.Descriptors.FileDescriptor[] {
               com.google.protobuf.DurationProto.getDescriptor(),
               com.google.protobuf.TimestampProto.getDescriptor(),
+              com.google.api.FieldBehaviorProto.getDescriptor(),
             });
     internal_static_google_spanner_v1_TransactionOptions_descriptor =
         getDescriptor().getMessageTypes().get(0);
@@ -117,7 +128,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_TransactionOptions_ReadWrite_descriptor,
             new java.lang.String[] {
-              "ReadLockMode",
+              "ReadLockMode", "MultiplexedSessionPreviousTransactionId",
             });
     internal_static_google_spanner_v1_TransactionOptions_PartitionedDml_descriptor =
         internal_static_google_spanner_v1_TransactionOptions_descriptor.getNestedTypes().get(1);
@@ -145,7 +156,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_Transaction_descriptor,
             new java.lang.String[] {
-              "Id", "ReadTimestamp",
+              "Id", "ReadTimestamp", "PrecommitToken",
             });
     internal_static_google_spanner_v1_TransactionSelector_descriptor =
         getDescriptor().getMessageTypes().get(2);
@@ -155,8 +166,22 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
             new java.lang.String[] {
               "SingleUse", "Id", "Begin", "Selector",
             });
+    internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor =
+        getDescriptor().getMessageTypes().get(3);
+    internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_fieldAccessorTable =
+        new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+            internal_static_google_spanner_v1_MultiplexedSessionPrecommitToken_descriptor,
+            new java.lang.String[] {
+              "PrecommitToken", "SeqNum",
+            });
+    com.google.protobuf.ExtensionRegistry registry =
+        com.google.protobuf.ExtensionRegistry.newInstance();
+    registry.add(com.google.api.FieldBehaviorProto.fieldBehavior);
+    com.google.protobuf.Descriptors.FileDescriptor.internalUpdateFileDescriptor(
+        descriptor, registry);
     com.google.protobuf.DurationProto.getDescriptor();
     com.google.protobuf.TimestampProto.getDescriptor();
+    com.google.api.FieldBehaviorProto.getDescriptor();
   }
 
   // @@protoc_insertion_point(outer_class_scope)
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/commit_response.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/commit_response.proto
index d44aad63b61..9e29c9ce9e0 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/commit_response.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/commit_response.proto
@@ -17,6 +17,7 @@ syntax = "proto3";
 package google.spanner.v1;
 
 import "google/protobuf/timestamp.proto";
+import "google/spanner/v1/transaction.proto";
 
 option csharp_namespace = "Google.Cloud.Spanner.V1";
 option go_package = "cloud.google.com/go/spanner/apiv1/spannerpb;spannerpb";
@@ -47,4 +48,13 @@ message CommitResponse {
   // For more information, see
   // [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
   CommitStats commit_stats = 2;
+
+  // Clients should examine and retry the commit if any of the following
+  // reasons are populated.
+  oneof MultiplexedSessionRetry {
+    // If specified, transaction has not committed yet.
+    // Clients must retry the commit with the new precommit token.
+    MultiplexedSessionPrecommitToken precommit_token = 4;
+    // (-- Room left for additional retry reasons in the future. --)
+  }
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/result_set.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/result_set.proto
index f392c1d7ddc..5c9b241bbff 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/result_set.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/result_set.proto
@@ -17,6 +17,7 @@ syntax = "proto3";
 package google.spanner.v1;
 
 import "google/protobuf/struct.proto";
+import "google/api/field_behavior.proto";
 import "google/spanner/v1/query_plan.proto";
 import "google/spanner/v1/transaction.proto";
 import "google/spanner/v1/type.proto";
@@ -53,6 +54,15 @@ message ResultSet {
   // Other fields may or may not be populated, based on the
   // [ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode].
   ResultSetStats stats = 3;
+
+  // A precommit token will be included if the read-write transaction
+  // is on a multiplexed session.
+  // The precommit token with the highest sequence number from this transaction
+  // attempt should be passed to the
+  // [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+  MultiplexedSessionPrecommitToken precommit_token = 5 [
+    (google.api.field_behavior) = OPTIONAL
+  ];
 }
 
 // Partial results from a streaming read or SQL query. Streaming reads and
@@ -157,6 +167,15 @@ message PartialResultSet {
   // This field will also be present in the last response for DML
   // statements.
   ResultSetStats stats = 5;
+
+  // A precommit token will be included if the read-write transaction
+  // is on a multiplexed session.
+  // The precommit token with the highest sequence number from this transaction
+  // attempt should be passed to the
+  // [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+  MultiplexedSessionPrecommitToken precommit_token = 8 [
+    (google.api.field_behavior) = OPTIONAL
+  ];
 }
 
 // Metadata about a [ResultSet][google.spanner.v1.ResultSet] or [PartialResultSet][google.spanner.v1.PartialResultSet].
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
index 301139210ed..8720c9849f7 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
@@ -899,6 +899,15 @@ message ExecuteBatchDmlResponse {
   // If all DML statements are executed successfully, the status is `OK`.
   // Otherwise, the error status of the first failed statement.
   google.rpc.Status status = 2;
+
+  // A precommit token will be included if the read-write transaction
+  // is on a multiplexed session.
+  // The precommit token with the highest sequence number from this transaction
+  // attempt should be passed to the
+  // [Commit][google.spanner.v1.Spanner.Commit] request for this transaction.
+  MultiplexedSessionPrecommitToken precommit_token = 3 [
+    (google.api.field_behavior) = OPTIONAL
+  ];
 }
 
 // Options for a PartitionQueryRequest and
@@ -1215,6 +1224,14 @@ message BeginTransactionRequest {
   // transaction, set it on the reads and writes that are part of this
   // transaction instead.
   RequestOptions request_options = 3;
+
+  // Required for read-write transactions on a multiplexed session that commit
+  // mutations but do not perform any reads or queries.
+  // Clients should randomly select one of the mutations from the
+  // mutation set and send it as a part of this request.
+  Mutation mutation_key = 4 [
+    (google.api.field_behavior) = OPTIONAL
+  ];
 }
 
 // The request for [Commit][google.spanner.v1.Spanner.Commit].
@@ -1262,6 +1279,14 @@ message CommitRequest {
 
   // Common options for this request.
   RequestOptions request_options = 6;
+
+  // If the read-write transaction was executed on a multiplexed session, the
+  // precommit token with the highest sequence number received
+  // in this transaction attempt, should be included here.
+  // Failing to do so will result in a FailedPrecondition error.
+  MultiplexedSessionPrecommitToken precommit_token = 9 [
+    (google.api.field_behavior) = OPTIONAL
+  ];
 }
 
 // The request for [Rollback][google.spanner.v1.Spanner.Rollback].
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
index 8af513d1563..0c1177c5995 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
@@ -18,6 +18,7 @@ package google.spanner.v1;
 
 import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
+import "google/api/field_behavior.proto";
 
 option csharp_namespace = "Google.Cloud.Spanner.V1";
 option go_package = "cloud.google.com/go/spanner/apiv1/spannerpb;spannerpb";
@@ -378,6 +379,13 @@ message TransactionOptions {
 
     // Read lock mode for the transaction.
     ReadLockMode read_lock_mode = 1;
+
+    // Clients should pass the transaction ID of the previous transaction
+    // attempt that was aborted if this transaction is being executed on a
+    // multiplexed session.
+    bytes multiplexed_session_previous_transaction_id = 2 [
+      (google.api.field_behavior) = OPTIONAL
+    ];
   }
 
   // Message type to initiate a Partitioned DML transaction.
@@ -512,6 +520,15 @@ message Transaction {
   // A timestamp in RFC3339 UTC \"Zulu\" format, accurate to nanoseconds.
   // Example: `"2014-10-02T15:01:23.045123456Z"`.
   google.protobuf.Timestamp read_timestamp = 2;
+
+  // A precommit token will be included in the response of a BeginTransaction
+  // request if the read-write transaction is on a multiplexed session and
+  // a mutation_key was specified in the
+  // [BeginTransaction][google.spanner.v1.BeginTransactionRequest].
+  // The precommit token with the highest sequence number from this transaction
+  // attempt should be passed to the [Commit][google.spanner.v1.Spanner.Commit]
+  // request for this transaction.
+  MultiplexedSessionPrecommitToken precommit_token = 3;
 }
 
 // This message is used to select the transaction in which a
@@ -539,3 +556,16 @@ message TransactionSelector {
     TransactionOptions begin = 3;
   }
 }
+
+// When a read-write transaction is executed on a multiplexed session,
+// this precommit token is sent back to the client
+// as a part of the [Transaction] message in the BeginTransaction response and
+// also as a part of the [ResultSet] and [PartialResultSet] responses.
+message MultiplexedSessionPrecommitToken {
+  // Opaque precommit token.
+  bytes precommit_token = 1;
+  // An incrementing seq number is generated on every precommit token
+  // that is returned. Clients should remember the precommit token with the
+  // highest sequence number from the current transaction attempt.
+  int32 seq_num = 2;
+}