diff --git a/pjlib/include/pj/config.h b/pjlib/include/pj/config.h
index 27a148e64..0e9eef1c6 100644
--- a/pjlib/include/pj/config.h
+++ b/pjlib/include/pj/config.h
@@ -25,6 +25,8 @@
  * @brief PJLIB Main configuration settings.
  */
 
+#error Development on this svn branch has been moved to trunk, please update your local copy with 'svn switch http://svn.pjsip.org/repos/pjproject/trunk'
+
 /********************************************************************
  * Include compiler specific configuration.
  */