diff --git a/configure.ac b/configure.ac
index fd2aeeee3e8124857f3686b3146561e2719e5849..33aad70e2ffc758d5236e69a613640b8c2198c88 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 
 dnl graph-tool package version number
 m4_define(graph_tool_version_major, 2)
-m4_define(graph_tool_version_minor, 18)
+m4_define(graph_tool_version_minor, 19dev)
 
 AC_INIT([graph-tool],
         [graph_tool_version_major().graph_tool_version_minor()],