Ok, this one is related to some ‘old’ server product, Lync 2013, but I have an excuse: there is a major reminder coming with it 
So the latest Cumulative Update for Lync Server 2013 (CU10) has been released (available here https://www.microsoft.com/en-us/download/details.aspx?id=36820), but this is not the major reminder; the major reminder is this is the LAST update for Lync Server.
Indeed, as per the support lifecycle, Lync Server 2013 is going to be out of main stream support in October 2018, which means only security updates will come through from then (extended support period). The complete out of support date (aka end of extended support period is November 2023. (see https://support.microsoft.com/en-us/lifecycle/search?alpha=Microsoft%20Lync%20Server%202013)
This is the moment, if not yet already started, to move from Lync 2013 to either Skype for Business or Skype for Business Online.