Assume that you install the September 2013 update package for Microsoft Lync 2013 that is mentioned in update 2825630. In this situation, your calendar information and OOF information aren’t synchronized between Microsoft Exchange and Lync 2013. For example, when a meeting is scheduled in your Outlook calendar, the following issues may occur:
If the meeting cannot be joined by using Lync 2010 or Lync 2013, your presence status isn't updated in Lync 2013 when the meeting starts.
If the meeting is a Lync 2010 or Lync 2013 meeting, your presence status isn’t updated in Lync 2013 until you join the meeting manually.
To resolve this issue, install the following update:
2825630 Description of the Lync 2013 update 15.0.4551.1005: November 7, 2013