diff --git a/go.mod b/go.mod
index 39ae60a..396f402 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module go.tmz.dev/musttag
 
-go 1.19
+go 1.21.0
 
 require (
 	go-simpler.org/assert v0.7.0
diff --git a/go.sum b/go.sum
index 3b8ed0b..6677112 100644
--- a/go.sum
+++ b/go.sum
@@ -3,6 +3,7 @@ go-simpler.org/assert v0.7.0/go.mod h1:74Eqh5eI6vCK6Y5l3PI8ZYFXG4Sa+tkr70OIPJAUr
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
+golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/tools v0.13.0 h1:Iey4qkscZuv0VvIt8E0neZjtPVQFSc870HQ448QgEmQ=
diff --git a/testdata/src/custom/go.mod b/testdata/src/custom/go.mod
index 84266ca..7cfa4d5 100644
--- a/testdata/src/custom/go.mod
+++ b/testdata/src/custom/go.mod
@@ -1,3 +1,3 @@
 module example.com/custom
 
-go 1.19
+go 1.21.0
diff --git a/testdata/src/go.work b/testdata/src/go.work
index 8e99d40..f8db9c3 100644
--- a/testdata/src/go.work
+++ b/testdata/src/go.work
@@ -1,4 +1,4 @@
-go 1.19
+go 1.21.0
 
 use (
 	./custom
diff --git a/testdata/src/tests/go.mod b/testdata/src/tests/go.mod
index 76894ba..9097142 100644
--- a/testdata/src/tests/go.mod
+++ b/testdata/src/tests/go.mod
@@ -1,6 +1,6 @@
 module tests
 
-go 1.19
+go 1.21.0
 
 require (
 	example.com/custom v0.1.0