Add deprecation notice

Change-Id: Iefd364fcaa740415938aeabc7af777555a43f1e3

README.md

diff --git a/README.md b/README.md
index e0d246a..5296e84 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,11 @@
-# Git Ref filter module for Gerrit
+# DEPRECATION NOTICE
+
+GerritForge has decided to [change the license to BSL](https://gitenterprise.me/2025/09/30/re-licensing-gerritforge-plugins-welcome-to-gerrit-enterprise/)
+therefore the Apache 2.0 version of this plugin is deprecated.
+The recommended version of the git-refs-filter plugin is on [GitHub](https://github.com/GerritForge/git-refs-filter)
+and the development continues on [GerritHub.io](https://review.gerrithub.io/admin/repos/GerritForge/git-refs-filter,general).
+
+# Git Ref filter module for Gerrit (DEPRECATED)
 
 Gerrit lib module to allow filtering out refs in the Git advertizing
 protocol phase.