Microsoft announces there is no major CU release for December 2021. Microsoft typically releases Cumulative Updates quarterly for Exchange Server 2019, 2016, and 2013.

There have been a number of critical Security Updates since the latest September 2021 CUs: see KB5007409, KB5007012.

For convenience, here are direct links to the Microsoft downloads for the latest Exchange versions:


Be sure to visit Messageware Security Products for Microsoft Exchange Server. All enterprises with Exchange Servers should add security that provides on-premise systems with logon intelligence and security controls protecting the most widely used Exchange Server services, including OWA / Outlook Web, ECP, Autodiscover, ActiveSync, EWS, OAB, MAPI, Outlook Anywhere. Critical additions for all enterprises including those who believe they are protected by multifactor authentication (MFA/2FA).