Update README.

README.markdown

@@ -41,6 +41,13 @@ running on the localhost on the default port:
     $value = $redis->get('library');
 
 
+The default server profile with this version of Predis is set to Redis 2.0, so if 
+you want to connect to a Redis 2.2 instance and leverage some of its new commands 
+you should initialize the client by specifying the correct profile:
+
+    $redis = new Predis\Client('127.0.0.1', '2.2');
+
+
 ### Pipelining multiple commands to a remote instance of Redis ##
 
 Pipelining helps with performances when there is the need to issue many commands