Exchange 2013 CU21

Cumulative Update 21 for Exchange 2013 is now available. It contains 10 documented new fixes or improvements, and all previously released fixes and security updates for Exchange 2013 as well as the latest DST updates. Note that mainstream support for Exchange 2013 has ended in April 2018.

Notable improvements, changes and fixes are;

  • .NET Framework 4.7.1 is now required.
  • VC++ 2013 runtime library is now required.
  • KB4133604: User can’t log on to a POP/IMAP account by using NTLM authentication in Exchange Server 2013
  • KB4058473: An Office 365 primary mailbox user cannot be assigned full access permissions for an on-premises mailbox in Exchange Server
  • KB4294205: POP3 services intermittently stop in an Exchange Server 2013 environment

This release includes no new updates to the Active Directory Schema.

Download: Cumulative Update 21 for Exchange Server 2013 (KB4099855)
Download: Exchange Server 2013 CU21 UM Language Packs
View: Description of Cumulative Update 21 for Exchange Server 2013
View: Blog post of the Exchange Team about CU21 for Exchange Server 2013