Symptoms
Microsoft Skype for Business Server 2015 installer may not update necessary drivers for Skype for Business Server 2015. For example, the Media Relay driver that's used by Skype for Business Server 2015 may not be updated silently, and some known issues cannot be fixed after you install certain updates. Meanwhile, you may find the version of the RTCMrDrv.sys file in the following location is 5.0.8308.241:
%WINDIR%\system32\drivers directoryThis issue occurs in the following scenario:
You have installed cumulative update 6.0.9319.249 for Skype for Business Server 2015. Meanwhile, you have installed any cumulative update after the cumulative update 6.0.9319.249 for Skype for Business Server 2015 after you install the cumulative update 6.0.9319.249.
Resolution
To fix this issue, install the February 2017 cumulative update 6.0.9319.277 for Skype for Business Server 2015, Front End server and Edge Server.
