Best Practices for Migrating from Exchange Server 2013 to Exchange Server 2019

Cpku011- You need to look at https://learn.microsoft.com/en-us/exchange/plan-and-deploy/supportability-matrix?view=exchserver-2019. Seperate from all the questions above, if you don't do so already, I strongly recomend you test first in an (isolated) test environment. In my experience, doing this has paid off many times over in the past couple years. For us this meant restoring backups (DCs, Exchange and client machines) to a completly clean test environment (pro-tip: you need to know how to do an authorative DC restore) and iterativly documenting a migration plan. In real terms, this ensured a nearly flawless transition from 2012R2 DCs + Exchange 2013 (on 2012R2)  to 2022 DCs + Exchange 2019 HA DAG (also on 2022) with little to no disruption.. Alternativly, hire a consultant; it's probably the most efficent path.