Yes, this is a deliberate act by Microsoft but it only affects he use of Outlook when using SMTP. Apparently you can get around this and avoid any program alterations by :- Using PowerShell (as Admin) to run the Set-TransportConfig cmdlet in the Exchange Online management module: Set-TransportConfig -AllowLegacyTLSClients $True Then configure a new SMTP endpoint of smtp-legacy.office3by attlebax - WinDev Forum