diff --git a/ChangeLog b/ChangeLog
index 40aa704235..8455feac92 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Feb 25 15:27:16 2015  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* tool/merger.rb: support 2.1+ versioning scheme.
+
 Tue Feb 25 08:49:12 2015  Kazuki Tanaka  <gogotanaka@ruby-lang.org>
 
 	* lib/cmath.rb (log): raise ArgumentError when more than 2 arguments
diff --git a/tool/mkconfig.rb b/tool/mkconfig.rb
index e874b3f407..7586fe6052 100755
--- a/tool/mkconfig.rb
+++ b/tool/mkconfig.rb
@@ -29,7 +29,7 @@ print %[
 # changes made to this file will be lost the next time ruby is built.
 
 module RbConfig
-  RUBY_VERSION == "#{version}" or
+  RUBY_VERSION.start_with?("#{version}"[/^[0-9]+[.][0-9]+[.]/]) or
     raise "ruby lib version (#{version}) doesn't match executable version (\#{RUBY_VERSION})"
 
 ]