We have a 2010 Exchange on premises configured with Hybrid right now. We have 3 mailboxes left on prem that should be moved to 365 in the next week or so. The objective is not to have any mailboxes hosted on prem, but install one 2016 or 2019 server for management, since that's still the requirement from MS. My questions are:
Should we install 2016 while 2010 is still in production? If so, I'm having some issues with that where 2016 throws a "Deserialization error:..." and would not let me proceed with the installation.
Should we decommission 2010 completely, then install 2016 or 2019 and use that for recipient management?
Would really appreciate some clarification and guidance on that.


