Cumulative Update 20 for Exchange Server 2013

Applies to: Exchange Server 2013 EnterpriseExchange Server 2013 Service Pack 1Exchange Server 2013 Standard Edition


Cumulative Update 20 for Microsoft Exchange Server 2013 was released on March 20, 2018. This cumulative update includes fixes for nonsecurity issues and all previously released fixes for security and nonsecurity issues. These fixes will also be included in later cumulative updates for Exchange Server 2013.

This update also includes new daylight saving time (DST) updates for Exchange Server 2013. For more information about DST, see Daylight Saving Time Help and Support Center.

Issues that this cumulative update fixes

This cumulative update fixes the issues that are described in the following Microsoft Knowledge Base articles:

  • 4073392 Description of the security update for Microsoft Exchange: March 13, 2018
  • 4073094 Emails outside a UID range are returned when you request for emails by using IMAP
  • 4073097 Monitoring probes of ECP.Proxy health checks fail on all CAS roles in Exchange Server 2013 and 2016
  • 4057216 Health mailbox's password is exposed in logs for a failed probe in Exchange Server 2016 and 2013
  • 4058384 Get-CalendarDiagnosticAnalysis shows DateTime in 12-hour clock in Exchange Server 2016 and 2013
  • 4057290 Incorrect user is returned in the ECP when one user's display name matches another user's alias
  • 4055433 User is added to an entire series when accepting a single instance through Exchange ActiveSync
  • 4058401 Administrator audit logging does not record Set-ServerComponentState cmdlet details in Exchange Server 2013 or 2016 environment
  • 4073095 "550 5.6.0 CAT.InvalidContent.Exception" and email isn't delivered in Exchange Server 2016 and 2013
  • 4058379 All cross-forest meeting updates have to be accepted again in Exchange Server 2016 and 2013
  • 4073093 Save issues occur when you use the plain Text Editor in OWA of Exchange Server 2013
  • 4073096 Emails sent from a shared mailbox aren't saved in Sent Items when MessageCopyForSentAsEnabled is True

Cumulative update information


The setup process for Exchange Server 2013 identifies any missing prerequisites.

Restart requirement

You may have to restart the computer after you apply this cumulative update package.

Registry information

You don't have to make any changes to the registry after you apply this cumulative update package.

Removal information

After you install this cumulative update package, you can't uninstall the package to revert to an earlier version of Exchange Server 2013. If you uninstall this cumulative update package, Exchange Server 2013 is removed from the server.

More Information

For more information about the deployment of Exchange Server 2013, see Release Notes for Exchange 2013.

For more information about the coexistence of Exchange Server 2013 and earlier versions of Exchange Server in the same environment, see Exchange 2013 System Requirements.

For more information about other Exchange updates, see Exchange Server Updates: Build numbers and release dates.


Learn about the terminology that Microsoft uses to describe software updates.