Setup: O365 tenant
Problem: Whenever a user is added to a O365 group the user will receive a standard notification. There are case when you do not want to send this message.
Solution:
Prerequsite : Microsoft.Exchange.Management.ExoPowershellModule
Run the following PowerShell commands:
# prerequisite Microsoft.Exchange.Management.ExoPowershellModule
Connect-EXOPSSession
$groupname = "<groupname>"
# Check if the message is enabled
Get-UnifiedGroup -Identity $groupname | select WelcomeMessageEnabled
# if enabled , run the next command to disable
Get-UnifiedGroup $groupname | Set-UnifiedGroup -UnifiedGroupWelcomeMessageEnabled:$false
# Check the result
Get-UnifiedGroup -Identity $groupname | select WelcomeMessageEnabled