diff --git a/configure.ac b/configure.ac
index 3897c5b3..19ff73b7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,9 +18,9 @@
 # 02111-1307  USA
 
 # We need a recent Autoconf to run a recent Autotest.
-AC_PREREQ(2.54)
+AC_PREREQ(2.56)
 
-AC_INIT([GNU Bison], [1.875a], [bug-bison@gnu.org])
+AC_INIT([GNU Bison], [1.875b], [bug-bison@gnu.org])
 AC_CONFIG_AUX_DIR(config)
 
 AM_INIT_AUTOMAKE([1.7 check-news readme-alpha dist-bzip2])