diff --git a/README.md b/README.md
index e6965b66e35..fa6b1bb2ca6 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,5 @@
+# This documentation is deprecated. Use https://github.com/mautic/developer-documentation-new instead.
+
 ### Mautic Developer Documentation ###
 
 Developer documentation for Mautic.