added note

Author: david

README.md

@@ -7,6 +7,10 @@ This plugin is a fork of the [original](https://github.com/Arcaniax-Development/
 but with many improvements and fixes.
 We aim to be always up-to-date and use new technology instead of hanging on to old and dead code.
 
+> [!IMPORTANT]
+> goPaintAdvanced only supports the latest version of Paper (1.20.6)
+> Therefor at least Java version 21 is required
+
 ## Major Changes
 
 ### Done