This article provides 5.2.11 HF1 (Hotfix-1) and information about how to apply this fix on your servers.
Important Notes
Hotfix files and script needs to be executed, if the v5.2.11 update was installed earlier then 20th May, 2015, other clients please ignore this fix. Script needs to be executed only in case if SfB (Lync) module is being used.
Latest Issues Fixed
Procedure