The following is a list of Exchange Cumulative Updates and Security updates for Exchange Server Subscription Edition, Exchange 2019 and Exchange 2016 as of December 15, 2025.

Important or interesting links:

• Exchange health checker – https://microsoft.github.io/CSS-Exchange/Diagnostics/HealthChecker/
• AV Exclusions – https://microsoft.github.io/CSS-Exchange/Setup/Set-ExchAVExclusions
• Exchange Extended Protection script – https://microsoft.github.io/CSS-Exchange/Security/ExchangeExtendedProtectionManagement

Exchange Server Subscription Edition

• Exchange Server SE RTM (KB5047155) – https://microsoft.com/en-us/download/details.aspx?id=108244
• Security Update for Exchange Server Subscription Edition SU4 (KB5071876) – https://www.microsoft.com/en-us/download/details.aspx?id=108493 

Exchange 2019 CU15

Support for Exchange 2019 ended on September 14, 2025. Microsoft will no longer publicly release any new Security Updates for Exchange 2019. Only Exchange Server Subscription Edition will be fully supported, and Microsoft will continue to deliver Security Updates and Hotfix Updates for Subscription Edition only!

• Cumulative Update 15 for Exchange Server 2019 (KB5042461) – https://www.microsoft.com/en-us/download/details.aspx?id=106402
• Hotfix Update for Exchange server 2019 CU15 SU5 (KB5066367) – https://www.microsoft.com/en-us/download/details.aspx?id=108419

Exchange 2019 CU14

• • Cumulative Update 14 for Exchange Server 2019 (KB5035606) – https://www.microsoft.com/en-us/download/details.aspx?id=105878
  • Hotfix Update for Exchange server 2019 CU14 SU8 (KB5066368) – https://www.microsoft.com/en-us/download/details.aspx?id=108421

Exchange 2016

Support for Exchange 2016 ended on September 14, 2025. Microsoft will no longer release any new Security Updates for Exchange 2016. Only Exchange Server Subscription Edition will be fully supported, and Microsoft will continue to deliver Security Updates and Hotfix Updates for Subscription Edition only!

Exchange 2016  CU23:

• Exchange 2016 CU23 (KB5011155) – https://www.microsoft.com/en-us/download/details.aspx?id=104132
• Exchange 2016 CU23 Language Pack – https://www.microsoft.com/en-us/download/details.aspx?id=104130
• Hotfix update for Exchange Server 2016 CU23 SU19 (KB5066369) https://www.microsoft.com/en-us/download/details.aspx?id=108420