Microsoft is still looking for a clear airport for its next significant Exchange Server release. As designers work through safety studies that were partially revealed by AI-assisted risk discovery, Exchange Server Subscription Edition Cumulative Update 1 has no known release time.

The Exchange Team stated on August 13, 2026, that changes must still be completed before they can be shipped. Administrators are left without a company CU1 implementation date and no excuse for postponing daily patching because Microsoft is continuing to release Exchange security updates.

The journey to CU1 is slowed by AI-assisted security function.

By the time the second quarter of 2026 was expected, Microsoft had anticipated CU1. The strategy for Exchange Server SE was updated on May 22 to target the next quarter of 2026, but the most recent CU1-specific release did not specify a firmer time.

Microsoft stated in its Aug. 13 CU1 release that Exchange is one of the team looking into problems that the business has identified as using AI to get risks. Engineers must also verify that each statement demonstrates a real safety issue, propagate it, create a fix, and validate regressions by testing for regressions.

The task is expected to be particularly demanding for Microsoft safety teams. More than 200 reported deficiencies were addressed in June’s Patch Tuesday, and 570 threats were fixed in July’s record-breaking transfer. More than 400 risks, including an deliberately exploited Windows zero-day, were patched by Microsoft in August.

CU1 also receives changes from exchanges. Microsoft insists that the combined update must take all the security updates that have been released since Exchange Server SE RTM, and that it won’t ship CU1 until it is immediately followed by another significant security upgrade.

A regular Security Update weighs less than CU1. The first SE discharge, which Microsoft describes as the first discharge of Exchange Server SE expected to create new capabilities, maintained code equality with Exchange Server 2019 CU15 plus future updates.

Priority continues to be given safety changes.

Instead of waiting ƒor CU1, officials may continue to αpply Sȩcurity Updates. Microsoft released the Exchange Server Security Updates for August 2026 on August 11 for Exchange Server SE, with changes likewise available for Exchange Servers that are available for the Exchange Server 2016 and 2019 Extended Security Update system.

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Companies that still use outdated Exchange editions are particularly at risk of this scheduling. Microsoft claims that there is no intention of moving the rest manufacturing machines to Exchange Server SE after the 2016 and 2019 Speak plan ends in October 2026.

Regular safety releases are still the top priority for deployment until Microsoft releases a company CU1 date. As of August 24, 2026, Microsoft’s most recent CU1-specific update is still available in the August 13 blog.