Features added and Improvements:
Manage contact groups
Skype for Business Online and Skype for Business Server 2015 users can now add and remove contact groups and enterprise distribution groups to their contact list.
Tag contacts for status change alerts
Skype for Business Online, Skype for Business Server 2015, and Lync Server 2013 users can tag a contact so that they are alerted any time the status of the contact changes to online.
Improved sender experience in the case when a recipient is unable to respond to incoming messages.
Fixed chat notification issues — In some cases, new chat notifications were not marked because the client assumed the user read them already.
Numerous fixes and reliability improvements so you get a more stable meeting experience.
Calendar syncing issues fixed so at start up meetings can be retrieved correctly.
Sign-in bug fixes — some account types were not able to sign in.
Contact group management features for Office 365 / Skype for Business Server 2015 customers
Contact tagging for status changes
Improvements to meetings reliability, sign-in, and chat