Microsoft blames AI for delayed Exchange update, can’t say when it will arrive

Microsoft has attributed delays to the release of a major Cumulative Update (CU) for its Exchange Server Subscription Edition (SE) to additional work generated by an AI bug-finding tool. In a post titled "Where is Exchange SE CU1 anyway?", the company's Exchange team admitted to customer inquiries regarding the anticipated release date of Exchange SE CU1.

Initially slated for the end of the first half of 2026, the CU1 release had since been pushed back to the second half of 2026. Exchange SE is the subscription version of Microsoft's email server, and a Cumulative Update is a new version that includes all recent bug fixes, features, and other changes. Microsoft's use of AI tools to identify vulnerabilities in its products has contributed to the delay, as the development team is currently working through reported issues, validating them, reproducing them, fixing, testing for regressions, and releasing updates monthly.

The Exchange team also cited its commitment to prioritizing security as another factor in the delay. While the team stated that CU1 is in progress and they aim to release it once a stable point is reached without pressing security updates, the exact date remains unspecified.