diff --git a/configure.ac b/configure.ac
index a3daedf9..8cb65717 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@ dnl Do not change user variables!
 dnl http://www.gnu.org/software/automake/manual/html_node/Flag-Variables-Ordering.html
 
 AC_PREREQ(2.61)
-AC_INIT([nghttp2], [0.7.12], [t-tujikawa@users.sourceforge.net])
+AC_INIT([nghttp2], [0.7.13-DEV], [t-tujikawa@users.sourceforge.net])
 LT_PREREQ([2.2.6])
 LT_INIT()
 dnl See versioning rule: