diff --git a/configure.ac b/configure.ac
index 8385ce743..f7f5f1139 100644
--- a/configure.ac
+++ b/configure.ac
@@ -16,7 +16,7 @@
 # problem to the user.
 AC_PREREQ([2.59])
 
-m4_define([ngspice_major_version], [40])
+m4_define([ngspice_major_version], [40+])
 m4_define([ngspice_minor_version], [0])
 m4_define([ngspice_version],
       [ngspice_major_version])
diff --git a/visualc/src/include/ngspice/config.h b/visualc/src/include/ngspice/config.h
index 5d98fb7d9..804859e93 100644
--- a/visualc/src/include/ngspice/config.h
+++ b/visualc/src/include/ngspice/config.h
@@ -15,7 +15,7 @@
 #define PACKAGE "ngspice"
 
 /* Version number of package */
-#define VERSION "40"
+#define VERSION "40+"
 
 /* Define the directory for executables */
 #define NGSPICEBINDIR "../bin"