Symptoms
This update improves the prominence of the stand-alone red exclamation point when an important message appears in the chat bubble in Microsoft Skype for Business 2015 (Lync 2013).
Resolution
To enable this feature, install the February 7, 2017, update (KB3161988) for Skype for Business together with the February 7, 2017, update for Office 2013 (KB3141491).
Note Lync 2013 was upgraded to Skype for Business in April 2015.