Note You can also install update KB2957927 from Windows Update. However, you must confirm that you are installing the update on Lync Server 2013 servers that are running Windows Server 2012 R2.
We do not recommend that you perform an in-place upgrade to Skype for Business Server 2015 if you deploy third-party Transport Driver Interface (TDI) filter drivers. Please contact support for help in determining whether your environment may encounter this issue.
How to determine whether a third-party TDI filter driver is loaded
To determine whether a third-party TDI filter driver is loaded, examine the following event that is logged in the System log when you restart servers:
Log Name: System Source: AFD Date: Date Time Event ID: 16001 Task Category: None Level: Warning Keywords: Classic User: N/A Computer: Computer FQDN Description: A TDI filter (\Driver\drivername) was detected. This filter has not been certified by Microsoft and may cause system instability.