Microsoft released updates for the various Lync 2013 mobile clients. The Apple client update addresses the 7.1 iOS bug, Android is just Android, and the Windows Phone client gets a tweak to the interface. Unfortunately all that seems to be updated is the interface as the push notification system is still a requirement for WP only. This push experience delivers a poor IM experience when multi-tasking but again, it is limited to the WP client.
On the Windows Phone 8.1 (currently preview) it has been noted by myself and other MVPs that the contact list does not fully populate after initial login. I personally use UCS, others do not, and experience the same result. The fix?? Simply log out of the app and back in and everything is happy.
Lync Server 2010 build number is 4.0.7577.230
Lync 2010 Client build number is 4.0.7577.4445
Lync Server 2013 build number is 5.0.8308.577
Lync 2013 Client build number is 15.0.4605.1003
Lync Group Chat build number is 4.0.7577. 4409
Lync Group Chat Server build number 4.0.7577.4409
Lync Group Chat Admin build number 4.0.7577.4409
Lync Attendee build number is 4.0.7577.4356
Lync Attendant build number is 4.0.7577.4098
Lync Phone Editions build number is 4.0.7577.4420
Lync 2010 for Windows Phone build number 4.3.8120.0
Lync 2010 for iPhone build number 4.7
Lync 2010 for iPad build number 4.7
Lync 2010 for Android build number 4.0.6509.3001
Lync 2013 for Windows Phone build number 5.4.1087.0
Lync 2013 for iPad build number 5.4
Lync 2013 for iPhone build number 5.4
Lync 2013 for Android build number 5.3.1100
Lync Basic 2013 build number is 15.0.4420.1017
Lync VDI 2013 build number is 15.0.4420.1017
It has been discovered that the latest Apple iOS upgrade 7.1 for iPhone, iTouch, and iPad devices breaks current Lync 2013 functionality. Specifically, it has been found that the update creates interoperability issues which causes voice and video to fail when using these devices. Microsoft is aware of the issue as seen in KB2955745 but there is currently no fix or workaround available.
The current solution? Hold off upgrading your Apple devices until a fix is found or you may be without Lync Audio/Video (I say might as Apple iPad Air and iPad Mini do not appear to exhibit the issue).
An update has been released and availabile in the iTunes store and may be foundhere. This update addresses the Apple flaw.