diff --git a/configure.ac b/configure.ac
index 4b1cad28..72724898 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,7 +24,7 @@
 # least Autoconf 2.59.
 AC_PREREQ(2.59)
 
-AC_INIT([GNU Bison], [2.2], [bug-bison@gnu.org])
+AC_INIT([GNU Bison], [2.2a], [bug-bison@gnu.org])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])