Today, we are announcing the availability of the 2025 H1 Cumulative Update (CU) for Exchange Server 2019 (aka CU15). This is the last CU we will release for Exchange Server 2019.
CU15 includes new ...
Updated Feb 26, 2025
Version 9.0
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I know this was for Nino who did answer, but my advice is to begin your Exchange Online migration as soon as possible. It is OK to skip CU15, but if any SUs are released after CU15, they will also be made available to CU14, and you should plan to install those if there are any.
If you have not finished migrating by October 14, 2025, any remaining servers will reach end of life on that day, and no more updates, bug fixes, SUs, etc., will be released. Any technically, your servers will be unsupported, although they will continue to operate without any loss of functionality. It is also likely that you won't need any support, except perhaps for the rest of your migration. And in that case, if you did call MS Support it would be in the context of a cloud migration, and they will absolutely help you.
Thanks for your reply Scott_Schnoll unfortunately, management wants to start the migration as close to EOL as possible. As of now, I believe if we start the first week of September , we will be okay.