For the second time this year, Microsoft has issued a clear reminder to system administrators: Exchange Server 2016 and Exchange Server 2019 are reaching their end of extended support. This critical deadline is set for October 14, 2025. While these servers will continue to function after this date, they will no longer receive essential support, including technical assistance, bug fixes, or security patches. To mitigate potential risks, Microsoft strongly recommends that administrators take action and upgrade their systems immediately.
The looming end-of-life date signifies more than just a lack of technical help. After the October deadline, Microsoft will stop providing fixes for new bugs that could impact the stability and usability of the outdated servers. Even more critical, the company will cease issuing security updates for any newly discovered vulnerabilities, leaving organizations exposed to potential breaches. To ensure the continued security and stability of their Exchange environments, administrators must move away from these unsupported versions.
Microsoft is providing two primary paths for administrators to follow. The first is to migrate to Exchange Online, which is available as a standalone service or as part of a Microsoft 365 subscription. This cloud-based option offers a modern, continuously updated solution. The second option is to upgrade to Exchange Server Subscription Edition (SE). For those currently on Exchange 2019, this upgrade can be done in-place, similar to a standard Cumulative Update.
For administrators using older versions, the upgrade path is slightly different. If you have Exchange 2016, Microsoft recommends a side-by-side upgrade to Exchange Server SE. However, if your organization is still running Exchange Server 2013 or an even older version, you must first remove it entirely before you can install Exchange Server 2019 or upgrade to the Subscription Edition. This step-by-step guidance is available in the company’s detailed documentation.
The company’s goal is to ensure all customers are on a supported and secure platform. This warning is a final call to action for administrators to avoid security risks and loss of critical support. By migrating to Exchange Online or upgrading to the Subscription Edition, organizations can protect their systems, secure their data, and ensure their messaging infrastructure remains reliable and up to date.
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