Updated December 7, 2022: We have updated the rollout timeline below. Thank you for your patience.
A common request from Exchange Online admins is for the ability to customize the message expiration timeout interval for messages sent by users in their organization. When a message in Exchange Online can’t be delivered or sent due to a temporary error, the message is queued for subsequent retries until either the message is delivered or sent, or until the message expires after the message expiration timeout interval has passed. In Exchange Online the service-wide default setting is 24 hours. With this update, we’ll now give admins the ability to customize the message expiration timeout interval for their organization from 12 hours to 24 hours.
This message is associated with Microsoft 365 Roadmap ID 93315.
A common request from Exchange Online admins is for the ability to customize the organizations message expiration timeout. When a message can’t be delivered immediately due to a transient error, it will queue up and be periodically retried until either the message is sent or until the message expires 24 hours later. For some messages, 24 hours can be too long to wait only to find out a message wasn’t delivered. So, we’re introducing the ability for admins to customize the message expiration timeout to be less than 24 hours.
When this will happen
We will begin rolling out in mid-October and expect to complete rollout by late December (previously late November).
How this will affect your organization
If you change the default 24 hour message expiration timeout to a lower value, messages sent by your users that are queued for retry will expire faster, and they will receive a bounce message (NDR) faster. For example, customizing it to 12 hours means senders will receive a bounce message after only 12 hours of retrying a message that can’t be sent, instead of 24 hours.
What you need to do to prepare
There is nothing you need to do to prepare for this.
Once the setting is available for your tenant if you want to change it for senders in your organization you can run the following Remote PowerShell cmdlet:
Set-TransportConfig -MessageExpiration <12..24>
Message ID: MC441064
Cloud instance(s): DoD, GCC High, Worldwide (Standard Multi-Tenant), GCC
Platform(s): Mac, Online, US Instances, Windows Desktop, World tenant