[German]Microsoft Exchange 2019 administrators have been asking themselves when CU 15, which has been overdue since 2024, will finally be released. Microsoft has now commented on this in a tech community article and also announced further innovations. Exchange 2019 and CU 15 are already prepared for Windows Server 2025.
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Waiting for CU15
It's strange, Microsoft has been trying to release two cumulative updates per year for Microsoft Exchange Server versions still in support since the beginning of 2020.
The cumulative updates (CUs) CU 14 and CU 15 for Exchange Server 2019 were actually announced for 2023. But the release was postponed by Microsoft to 2024, as I reported at the end of November 2023 in the blog post Exchange Server 2019: No more CUs in 2023; CU14 and CU15 coming in 2024.
CU 2024 H2 for Exchange Server 2019 was then scheduled for the second half of 2024. However, this cumulative update has not yet been released by Microsoft. The release in December 2024 was postponed to January 2025 due to Christmas. I pointed this out in the article Exchange Server 2019: CU15 delayed until January 2025.
Microsoft comments on CU15
But January 2025 was over pretty damn quickly, barely started before it was February 1, 2025 and there was still no sign of CU15. But at least Microsoft has managed to get around to releasing some information, even if there is no CU15.
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In the Techcommunity article When is Exchange 2019 CU15 coming (and more news), Microsoft discusses the "whereabouts" of CU15 on January 31, 2025. CU 15 has been renamed H1 2025 CU due to the above-mentioned postponement. But Microsoft says it is still not ready to release the CU15. This is indeed an unexpected delay, Microsoft admits. To be fair, Microsoft does give good reasons for the delay.
- Exchange 2019 CU15 is the last CU for Exchange 2019. Exchange Server CU15 is the "code equivalent" of the Exchange Subscription Edition (SE) RTM version. Therefore, CU15 is the last chance Microsoft has to release any Exchange features before Exchange SE CU1. CU15 contains new features that increase the complexity of this version.
- As part of the validation of new CU releases, it was sent to customers in the TAP program. As part of this program, Microsoft received information about some late issues with CU15. This led to the decision to fix them and create a new CU15 build.
The last point will hopefully prevent half-baked releases from being unleashed on administrators. Microsoft indicates that the testing process had to be reset several times due to bugs and this extended the time to release. But they are now "almost ready" for the release of CU 15.
Microsoft confirms in the article that both CU14 and CU15 provide support for running Exchange Server 2019 on Windows Server 2025. This means that administrators can install either CU14 or CU15 on new hardware running Windows Server 2025 and then upgrade directly to Exchange Server Subscription Edition (SE) to take advantage of the server's maximum supported product lifecycle.
Microsoft recommends that administrators continue working on the migration to Exchange Server Subscription Edition (SE). Its release is planned for the second half of 2025 (2H2025).
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Exchange Server 2019: No more CUs in 2023; CU14 and CU15 coming in 2024
Exchange Server 2019: CU15 delayed until January 2025
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