How to exclude signatures on Planner or Teams comments

Scenario

You notice that every message or comment in Microsoft Planner or Microsoft Teams gets a signature, making the thread longer than necessary. You wish to exclude signatures on Planner or Teams comments.

Resolution 

To exclude signatures for messages being sent using Microsoft Planner or Microsoft Teams, you can add an exception to the Identify messages to send to Exclaimer mail flow rule in Exchange Online.

To add the exception:

1. Sign in to the Exchange Online admin portal (https://admin.exchange.microsoft.com) as an Administrator.
   
   The Exchange admin center is displayed.
   
   
2. From the left-hand navigation menu, select Mail flow, then select Rules.
   
   
3. In Rules, edit the Identify messages to send to Exclaimer rule.
   The details are displayed on the right-hand pane.
   
   
4. Click Edit rule conditions.
   
   Example:
   
   
   
5. In Except if, click + (add exception).
   
   
6. From the Or drop -down list, select, A message header.... From the adjacent drop-down list select Includes any of these words.
   
   
7. Enter the header name as:
   X-MS-Exchange-UnifiedGroup-SubmittedViaGroupAddress
   
   
8. Enter the following text:
   /o=ExchangeLabs/ou=Exchange Administrative Group
   
   
9. Click Save.
   

   Once the exception is added, the transport rule will look something like this: 

   

10. Click Save