Lync IP phone firmware updates for all phone models will be released for download starting Friday 4/27/2012 5:00pm. The new version (4.0.7577.4066) provides users the ability to override their UC integrated presence state from the IP phone menu. It also includes various bug fixes documented at http://support.microsoft.com/?kbid=2672349
IP phones that are online and signed in will periodically check for updates (once every 24 hours) and download the latest released version. Once downloaded, the phones will reboot after ~10 minutes of inactivity. No user action required to perform the upgrade. All IP phones that are online and signed in should be upgraded by Monday 4/30/2012 8:00am