Release 0.5.9.1.
diff --git a/configure.ac b/configure.ac
index 4c2c179..9c4ced8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT(dash, 0.5.9)
+AC_INIT(dash, 0.5.9.1)
 AM_INIT_AUTOMAKE([foreign])
 AC_CONFIG_SRCDIR([src/main.c])