Exchange Server Roadmap Update

Echoing the overlapping support commentary.

We are on Exch 2016 CU23, no intention of moving to the cloud (we're hybrid already but on prem for mailbox content) and good to hear MS acknowledging there are reasons for on prem and dismissing certain commentators snark 🙂

But...

We switched from a godawful legacy non MS Mail system to Exchange, finally, in 2017 or so. Big project. 2019 came out, we didn't want to make that jump too soon given the acknowledged complexity involved and fully expected that Exchange 2022 would be our next upgrade.

Then 2022 didn't happen, and we heard nothing for ages and ages and we finally have an update, which is very welcome. In the meantime we hedged our bets, in the hopes that MS would understand what organisations like ours are dealing with and would extend 2016 support to give a sufficient overlap period for us to go straight (in legacy upgrade mode) to Exchange 2025 or whatever it ended up being called. 

But...

Exchange 2016 CU23 goes out of extended support in mid October 2025. 

Exchange SE doesn't release until "early Q3" 2025 assuming ye don't slip again.  So we may infer say late July?

That gives about a 3 month period in which we have the opportunity to do the upgrade from 2016 to the next-plus-one release of exchange rather than having to do two upgrades. It isn't our fault there's a 9 year gap between those "next-plus-one" releases.

No large organisation in their right mind jumps to a new release that early, even with assurances that there are no changes to the code, but how do we know for example that there won't be some issue with Outlook or some other component having an issue with the updated build numbers or some such.  Given the frequency with which things like outlook search break, it's already a bit flakey.  If we ran into an issue, and had to delay a bit, we're out of support.

Hence our, and i believe others on this thread, hope that MS would extend that support overlap period to prevent customers essentially through no fault of their own ending up with their exchange server out of support, unless they were in a position to launch major spends and major projects.

So first question is, what does "unsupported" mean. If we were still on exchange 2016 CU23 on October 14th 2025 what happens? Do we just not get security updates, or does outlook stop talking to our exchange servers, or does our hybrid exchange connectivity go down?

Now, all of that said, if I've read the article correctly, we do not as I originally feared need to do two legacy upgrades i.e. upgrade from 2016 to 2019 by rebuilding servers and building new databases and migrating mailboxes, and then going from 2019 to SE by reinstalling exchange and creating new databases and migrating users. All of which involves third party contractor support and fitting that in amongst a full calendar of projects.

We can instead do an upgrade to 2019 at our leisure, when we can book in our third party support, then when SE arrives, run a CU type install process ourselves inhouse to lift Exch 2019 to Exch SE, on the same server, within the same DAG, without creating new databases and all the storage implications that entails, and without having to migrate mailboxes into new databases, and with minimal fears, correct?

If i've read the comments properly i believe we could even if we really wanted to, do a legacy 2016 to SE upgrade and skip 2019 entirely but that, given the tight overlap period, would be madness. 

So, if the 2016 legacy upgrade to 2019 at our leisure followed by easy CU-style uplift to SE is true, that is actually a pretty good plan and to be fair a decent compromise between what we might have wished for and the reality we have.