Microsoft have just announced the latest
cumulative update for Lync server 2013 update for the Lync 2013 client.
Edit: Turns out this is actually a client patch, which wasn’t telegraphed too well when the patch was first announced, hence the confusion. Regardless, it’s an impressive list of fixes which you should consider testing in your lab before deploying to your users.
There are a number of fixes and feature additions, including fixes to desktop sharing, speeding up of network recovery after a loss, and the addition of a button which displays when a user is connected to a backup pool which will display what features are going to be lost.