update release notes, more content about Volto and ClassicUI

release/RELEASE-NOTES.md

@@ -5,7 +5,7 @@
 * Read the [upgrade guide](https://6.docs.plone.org/upgrade/index.html), explaining the biggest changes compared to 5.2.
 * Canonical place for these [release notes](https://dist.plone.org/release/6.0.3/RELEASE-NOTES.md) and the full [packages changelog](https://dist.plone.org/release/6.0.3/changelog.txt).
 
-For technical wizards who want to jump straight in, here are two important links:
+If you want to jump straight in, here are two important links:
 
 * With pip you can use the constraints file at [https://dist.plone.org/release/6.0.3/constraints.txt](https://dist.plone.org/release/6.0.3/constraints.txt)
 * With Buildout you can use the versions file at [https://dist.plone.org/release/6.0.3/versions.cfg](https://dist.plone.org/release/6.0.3/versions.cfg), plus optionally [`versions-extra.cfg`](https://dist.plone.org/release/6.0.3/versions-extra.cfg) and [`versions-ecosystem.cfg`](https://dist.plone.org/release/6.0.3/versions-ecosystem.cfg).
@@ -15,9 +15,10 @@ For technical wizards who want to jump straight in, here are two important links
 
 Major changes since 6.0.2:
 
-* `plone.base`: Move `plone.app.layout.navigation.root.getNavigationRoot` to `.navigationroot.get_navigation_root`.
-  Move `plone.app.layout.navigation.root.getNavigationRootObject` to `.navigationroot.get_navigation_root_object`.
-  Both are essential basic functions in Plone and not layout related at all.
+* `plone.base`: Move `getNavigationRoot` and `getNavigationRootObject` from `plone.app.layout` to `plone.base.navigationroot.get_navigation_root_object`.
+  This is part of a general move of essential basic functions to the `plone.base` package.
+  This is a prerequisite of further decoupling and cleanup of dependencies, so the core of Plone can become smaller.
+  Backwards compatible imports are left in `plone.app.layout`, so add-on packages do not need to change anything.
 * `Zope`: Replace `cgi.FieldStorage` by `multipart` avoiding the `cgi` module deprecated by Python 3.11.
   Mark binary converters with a true ``binary`` attribute.
   Fix encoding handling and ``:bytes`` converter.
@@ -34,9 +35,18 @@ Major changes since 6.0.2:
 
 ## Volto frontend
 
-The default frontend for Plone 6 is Volto. Latest release is [16.18.0](https://www.npmjs.com/package/@plone/volto/v/16.18.0).  See the [changelog](https://github.com/plone/volto/blob/16.18.0/CHANGELOG.md).
+The default frontend for new Plone 6 sites is Volto. Latest release is [16.18.0](https://www.npmjs.com/package/@plone/volto/v/16.18.0).  See the [changelog](https://github.com/plone/volto/blob/16.18.0/CHANGELOG.md).
 Note that this is a JavaScript frontend that you need to run in a separate process with NodeJS.
-The Classic UI is still available when you only run the Python process.
+
+Also, existing Plone sites need some or more extensive changes to be upgraded before they can use the Volto Frontend. Please read the guide on [migrating from Plone Classic UI to Volto](https://6.docs.plone.org/backend/upgrading/version-specific-migration/migrate-to-volto.html).
+
+When you use containers, you need both `plone/plone-backend` and `plone/plone-frontend`.
+
+
+## ClassicUI
+
+The Classic UI is still available as an option, especially for existing sites.
+When you use containers, you only need `plone/plone-backend`.
 
 
 ## Python compatibility