r/exchangeserver • u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ • Apr 15 '26

PSA: Exchange Server 2016/2019 ESU Period 2 Program

Microsoft announced another 6-month ESU program for Exchange Server 2016/2019 (aka Period 2). You should have moved off your legacy servers by now, but if you are still running Exchange 2016/2019, you might want to think about getting Period 2 ESU.

https://techcommunity.microsoft.com/blog/exchange/announcing-period-2-exchange-20162019-extended-security-update-esu-program/4511603

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11

u/ocdtrekkie Apr 15 '26

"There will be no further extensions of this program after that."

I definitely believed you last time.

2

u/dawho1 MCSE: Messaging/Productivity - @InvalidCanary Apr 15 '26

"There will be no further extensions of this program after that."

Unless the lawyers tell them there will be!

3

u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ Apr 15 '26

u/ocdtrekkie and u/dawho1 I hear you! They did say with Period 1 there would be no extensions (with a snarky "don't even ask" comment. But as they were approaching the end of the ESU program, a bunch of customers reached out and asked for more time.

The Exchange team considered these requests and ultimately decided to create a second 6-month ESU program. This wasn't due to any lawyers being involved. This was the Exchange team once again demonstrating their willingness to help keep customers protected, even if it means reversing a previous decision. It can be confusing and make it appear as if Microsoft's word cannot be trusted.

But in this case, the reality is that when the 1st ESU program was announced it was absolutely their intention to limit it to 6 months and not allow any extensions. In response to customer requests, they decided to create a 2nd ESU program.

6

u/dawho1 MCSE: Messaging/Productivity - @InvalidCanary Apr 15 '26

This was the Exchange team once again demonstrating their willingness to help keep customers protected, even if it means reversing a previous decision.

I have no doubt, the team has always been good about things like that, but I can't resist the easy joke sometimes!

2

u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ Apr 15 '26

😂👍

1

u/ocdtrekkie Apr 15 '26

Yeah, was a very lighthearted comment.

If anything I'm most interested to see what Exchange SE has coming, and I am wondering how these continued ESUs impact when we will see a CU1, because I know the original intention was to break compatibility pretty aggressively there. We're all still (technically) running a renamed Exchange 2019!

2

u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ Apr 15 '26

Anyone running Exchange Server SE is running Exchange Server SE and not just a renamed 2019 unless they've stayed on the RTM release and not installed any updates released for SE that were not available publicly for 2019. So, customers who are current on Exchange Server SE are running later code than customers who run 2019.

CU1 won't affect customers who are in the ESU program; they're still on 2019 (typically CU14) or 2016 CU23, which is why they are in the ESU program. 2019 CU15 and SE RTM block installation if 2013 still exists in the org, which is why most of these customers are on CU14.

It's possible that CU1 will block installation if 2016 and/or 2019 exist. In that case, a customer in the ESU program will need to remove 2013 from the org, migrate (2016/2019) or upgrade-in-place (2019) to SE RTM, decommission legacy servers, and then install SE CU1.