Hello,
I know Exchange 2007 is no longer supported, but I have a customer that is running this old version. I plan to introduce Exchange 2013 into the organization, and then move everything off, decommission the 2007 servers, and then install 2016 and move everything to 2016. My question is should I try to introduce the latest CU of Exchange 2013, or should I use an older one that is know to work with Exchange 2007 coexistence? Also, is it possible to introduce a a new server with an older 2013 CU after a server with a newer CU is introduced (in case there are problems)? Thanks!