I've got multiple Exchange server 2013 Standard mailboxes scattered around 3 different AD sites (same domain).
AD Site 1 - PRODEXC1-VM - Mailbox Server &CAS Role - SP1
AD Site 2 - PRODMBX01-VM - Mailbox Server - SP1
AD Site 3 - PRODEXC2-VM - Mailbox Server &CAS Role - SP1+CU3
I'd like to deploy additional 3x Mailbox server on each site so that I can build DAG for each AD site.
As I read today, the latest CU is CU16, so can I install the new 3x mailbox server above with CU16 while the other is still as is ?
This is to avoid any outage.