README.md in ffi-msgpack-0.1.3 vs README.md in ffi-msgpack-0.1.4

- old
+ new

@@ -77,10 +77,10 @@
     end
 
 ## Requirements
 
 * [libmsgpack](http://msgpack.sourceforge.net/) >= 0.5.0
-* [ffi](http://github.com/ffi/ffi) >= 0.6.0
+* [ffi](http://github.com/ffi/ffi) ~> 0.6.0
 
 ## Install
 
     $ sudo gem install ffi-msgpack
 