@DustinB3403 Yeah, Exchange 2013 and over. You have to also be on the last 2 Cumulative Updates from Exchange 2013, 2016 or 2019. For 2019 You only can get the updates through Microsoft Volume Licensing.
Yeah, a customer attempted an update from 2016 CU15.1 to CU19, it errored out on the last step, they restored (bad move) and had some mail flow issues for a bit.
But they are back online now