Notification for migrated Users during Cross-Tenant Migration
It is important for users informing other about their status or migration. Therefore, Exchange Online offers good solution, the Out Of Office Message.
User might even receive a new DNS domain in some cases.
For good user experience, internal and external persons could be informed. Out of Office messages are also visible in Microsoft Teams.
User the cmdlet Set-MailboxAutoReplyConfiguration
Set-MailboxAutoReplyConfiguration -Identity firstname.lastname@example.org -AutoReplyState Enabled -InternalMessage "I'm migrated to TARGET." -ExternalMessage "Due to our company merger, I'm migrated to COMPANY, you will be able contacting me at email@example.com." -ExternalAudience All