I'm starting a Lotus Domino to Exchange Online migration project that will last 4 weeks. So during the project I have some users on Lotus Domino and some users on Exchange Online.
One of the first problem you will encounter is that the users on Lotus Domino receiving emails with attachments from the Exchange Online users will see the attachments as "WINMAIL.DAT".
To avoid this, first, connect to Exchange Online :
$LiveCred = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $LiveCred -Authentication Basic -AllowRedirection
Once connected, I entered this command :
Set-RemoteDomain Default -TNEFEnabled $false