diff --git a/configure.ac b/configure.ac
index e165a2c15..4283d528a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 AC_PREREQ([2.61])
-AC_INIT([spot], [2.3.1], [spot@lrde.epita.fr])
+AC_INIT([spot], [2.3.1.dev], [spot@lrde.epita.fr])
 AC_CONFIG_AUX_DIR([tools])
 AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([1.11 gnu tar-ustar color-tests parallel-tests])