Microsoft Exchange Server Updates

Microsoft’s Shift in Servicing Cadence

In a move that reflects a commitment to both innovation and stability, Microsoft announced last year a change in its servicing model for Exchange Server. This strategic shift saw the company adopt a twice-yearly release schedule for Cumulative Updates (CUs), targeting the first and second halves of each calendar year. These updates, set for March and September releases, are designed to ensure quality and responsiveness to emerging needs, occasionally prioritizing critical updates like Security Updates (SUs) over regular CU releases.

Adjustments to the 2023 CU Schedule

As the end of 2023 approaches, Microsoft has made a significant announcement: there will be no CU release in H2 2023. This decision, attributed to the calendar’s constraints and a policy of not releasing CUs in December, mirrors a similar approach taken last year.

Focus on Exchange Server 2019: Final CUs Approaching

The spotlight now turns to Exchange Server 2019, which is set to receive the final two CUs, CU14 and CU15, in H1 and H2 of 2024. Notably, CU14’s release, initially planned for this year, has been postponed to January 2024. This update is particularly noteworthy, bringing enhancements such as TLS 1.3 support, an S/MIME control fix, and Extended Protection activated by default, among other features.

Navigating the End of Mainstream Support

A point of potential confusion for many in the tech field is the release of CUs post-mainstream support. Exchange Server 2019, for example, will see its mainstream support end on January 9, 2024. However, this date is not a cutoff for CU releases but rather the final date for submitting bug fixes or Design Change Request (DCR). Post this date, Microsoft’s focus will shift to considering only security fixes. This policy means that while mainstream support ends, Microsoft remains committed to resolving issues filed before the cutoff, leading to CU releases even after the end of mainstream support.

Lifecycle Policy and End of Life Dates

  • Microsoft adheres to a fixed lifecycle policy for all versions of Exchange Server, providing a total of 10 years of support—5 years each of mainstream and extended support.
  • The end-of-life dates for various versions are as follows:
    • Exchange Server 2013: April 11, 2023
    • Exchange Server 2016: October 14, 2025
    • Exchange Server 2019: October 14, 2025


For tech professionals managing or utilizing Microsoft Exchange Server, these updates are critical. They demonstrate Microsoft’s commitment to a balanced approach between introducing new features and maintaining the stability and security of their systems. Understanding these changes is essential for effective planning and management of Exchange Server environments, ensuring that systems remain secure, functional, and up-to-date with the latest improvements and fixes.