README.md in mercenary-0.2.1 vs README.md in mercenary-0.3.0

@@ -16,9 +16,11 @@
 
 Or install it yourself as:
 
     $ gem install mercenary
 
+**Note: Mercenary may not work with Ruby < 1.9.3.**
+
 ## Usage
 
 ```ruby
 Mercenary.program(:jekyll) do |p|
   p.version Jekyll::VERSION