diff --git a/configure.ac b/configure.ac
index 6f86e2ad5..e70f33783 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,8 +3,8 @@ dnl STATUS: "X" for prerelease beta builds,
 dnl         "Z" for unsupported trunk builds,
 dnl         "0" for stable, supported releases
 dnl these should be the only two lines you need to change
-m4_define([user_agent_prefix],[2.12])
-m4_define([peer_id_prefix],[-TR2120-])
+m4_define([user_agent_prefix],[2.12+])
+m4_define([peer_id_prefix],[-TR212Z-])
 
 AC_INIT([transmission],
         [user_agent_prefix],