Microsoft has pushed the final Cumulative Update for Exchange Server 2019 into 2025.
It's good news for Exchange Server administrators hoping for a quiet festive season after the problematic November 2024 Security Update (SU) that broke transport rules and disrupted the flow of email for some users.
In 2022, Microsoft announced that it would be moving to a March and September cadence for its Cumulative Updates (CUs). However, it said that since "our release dates are driven by quality," those CUs might slip to April and October or later.
The company also acknowledged that "customers ... tell us that December is not a good time to release a CU," and so here we are. The final CU for Exchange Server 2019 has slipped into 2025. It also missed the end-of-year cutoff in 2022 and 2023, so administrators would be forgiven for expecting something similar in 2024, particularly considering all the problems around the November 2024 SU, which ended up being pulled and re-released after the bugs were resolved.
While the numbering will remain the same – the final CU for Exchange Server 2019 will be CU15 – it will be referred to as the H1 2025 CU rather than the H2 2024 CU. It will also arrive in early January 2025.
Time is getting short for Exchange Server 2019. While the CU has been pushed back to 2025, Microsoft is sticking with the planned lifecycle of Exchange Server 2019, which is due to drop out of support on October 14, 2025. The successor to Exchange Server 2019, Exchange Server SE, is still expected in early H2 of 2025.
After a hectic end of 2024 for some Exchange Server administrators, the official confirmation that the CU is heading into 2025 will mean the next few weeks should be quiet. Unless, of course, something breaks in the meantime.
2025, however, will be a busy year. Microsoft said: "Our guidance for all customers remains the same: get to Exchange Server 2019, install the latest update, and upgrade in-place to Exchange Server SE when available." ®