S/MIME signed reply draft behaves like the first message in conversation in Exchange Server 2019 and 2016

Applies to: Exchange Server 2019Exchange Server 2016


In Microsoft Exchange Server 2019 or Exchange Server 2016, consider the following scenario:
  • User A sends an email message to User B.
  • User B composes a reply by adding a S/MIME (Secure/Multipurpose Internet Mail Extensions) signature.
  • User B saves the reply as a draft.
In this scenario, you find that the draft of the reply does not have a value for the InReplyTo property.


To fix this issue, install one of the following updates:
For Exchange Server 2019, install the Cumulative Update 3 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.
For Exchange Server 2016, install the Cumulative Update 14 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.


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