Add deprecation notice

Change-Id: Idb868505138e1b77e57c606cd5fa2d0b5fd9fae8

README.md

diff --git a/README.md b/README.md
index 916e48c..9dcf54b 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,11 @@
-Gerrit Groovy Provider Plugin
+# 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 groovy-provider plugin is on [GitHub](https://github.com/GerritForge/groovy-provider)
+and the development continues on [GerritHub.io](https://review.gerrithub.io/admin/repos/GerritForge/groovy-provider,general).
+
+Gerrit Groovy Provider Plugin (DEPRECATED)
 =============================
 
 This plugin provides Groovy runtime environment for Gerrit plugins in Groovy.