diff --git a/configure.ac b/configure.ac
index 36eca06b..73c2b3c1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([netgen],[5.0-dev],[],[])
+AC_INIT([netgen],[5.1-dev],[],[])
 AM_INIT_AUTOMAKE([-Wall -Werror foreign])
 
 AC_CONFIG_MACRO_DIR([m4])