Skype for Business 2015 users are getting a January 2019 update for the communication system. The update became available on January 2 and contains the usual amalgam of fixes and performance enhancements, but this particular update includes the new Skype for Business client software.
Microsoft has released an update for Microsoft Skype for Business 2015 (Lync 2013) on January 2, 2019. This update also includes the new Skype for Business client. The version number of this update is 15.0.5101.1002.