nixos/dovecot: support 2.4

Co-authored-by: Jappie3 <jappie3+git@jappie.dev>

Author: Prince213

doc/release-notes/rl-2605.section.md

@@ -63,6 +63,9 @@
 
 - `corepack_latest` has been removed, as Corepack is no longer distributed with Node.js.
 
+- `dovecot` default version has been updated from 2.3 to 2.4.
+  This introduces some breaking changes; Refer to the [upstream migration article](https://doc.dovecot.org/2.4.2/installation/upgrade/2.3-to-2.4.html) for details.
+
 - `nodePackages.browser-sync` has been removed, as it was unmaintained within nixpkgs.
 
 - `spoof` has been removed, as there are many issues upstream with it working on modern OS versions, and it appears to be unmaintained.

nixos/doc/manual/release-notes/rl-2605.section.md

@@ -157,6 +157,8 @@ See <https://github.com/NixOS/nixpkgs/issues/481673>.
 
 - Budgie has been updated to 10.10, please check the [upstream announcement](https://buddiesofbudgie.org/blog/budgie-10-10-released) for more details.
 
+- `services.dovecot` now supports the Dovecot 2.4 configuration format while maintaining compatibility with Dovecot 2.3.
+
 - `services.frp` now supports multiple instances through `services.frp.instances` to make it possible to run multiple frp clients or servers at the same time.
 
 - `hyphen` now supports over 40 language variants through `hyphenDicts` and now allows to enable all supported languages through `hyphenDicts.all`.