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 Changelog
 =========
+# v2.2.0 (June, 14, 2016)  
+* SDK Internal timer logic is changed.
+* Performance Improvement
+* Fixed a bug `NullReferenceException` in `SendBirdSDK.SendMessage`
+
 # v2.1.2 (June, 10, 2016)  
 * SendBirdSDK.GetConnectionState() is added.
 
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