Lync 2013 May 2015 Update Rebrands Lync Regardless Of UI Preference

As described in this support article https://support.office.com/en-ca/article/Why-do-I-see-Skype-for-Business-when-Im-using-Lync-50935112-4978-46b8-b2ad-9dd7b81365bf?ui=en-US&rs=en-CA&ad=CA&fromAR=1, the most recent patch to Office 2013 will rebrand the Lync client to "Skype for Business (Lync)" and display the Skype for Business tray icon when the client UI is set to Lync 2013. 

 

It is recommend that administrators prepare for the update before deploying - https://blogs.technet.com/b/office_sustained_engineering/archive/2015/05/08/skype-for-business.aspx