diff --git a/Makefile.config b/Makefile.config
index 7b05eae..9c86a46 100644
--- a/Makefile.config
+++ b/Makefile.config
@@ -1245,11 +1245,11 @@ EXT=
 
 # The calc version in the form of x.y.z.w
 #
-VERSION= 2.16.0.0
+VERSION= 2.15.1.2
 
 # The calc major version in the form of x.y.z
 #
-VER= 2.16.0
+VER= 2.15.1
 
 # Names of shared libraries with versions
 #