Retiring on prem Exchange server from O365 hybrid while keeping AD sync

[Tony-Bluefly]

Hi All,

   We have several Exchange/Office 365 hybrid environments and we are now starting to look at retiring the no longer needed on premises exchange server while still retaining AD sync via AAD Connect. We are looking for best practice documentation to achieve this but have been unsuccessful finding anything for this particular situation. Currently the emails are still being sent through the Exchange server which then passes on to Office 365. So we're looking at how to make the emails go direct to Office 365 and then removing/uninstalling the Exchange server from the environment. Any suggestion would be greatly appreciated!

Tony

[#2]

Still not a supported scenario. Technically you can remove the last server and make updates via adsi or attributes tab on ADUC or ideally if you can go all cloud removing azure ad connect will then allow cloud management of exchange attributes.

Anyway this is a good ignite session going over some of this and things to consider. https://youtu.be/XHFleM6OElc

[#3]

To start, redirect the mail flow by changing the MX record and rerunning the Hybrid wizard to adjust connectors and such. Once you've confirmed everything is working as expected, you can start the removal process, by following the steps here: https://docs.microsoft.com/en-us/exchange/decommission-on-premises-exchange

As Chris mentioned above, you need to have at least one server for management purposes, that's a requirement for any scenario involving dirsync. If you want to stay in a "supported" configuration, that is.