@PeterForster Sorry but Microsoft is not talking here about the new Outlook for Windows for Enterprise Accounts. In fact it does not mention this anywhere in the post. Is talking about the new Outlook for Windows commercial customers not Enterprise Accounts. A lot of commercial customers are using Google GMail accounts (or Yahoo or other professionals email providers) in Outlook. But the New Outlook first requieres a Microsoft account to at least, to run and open. Classic Outlook not. And second requieres you to send to Microsoft the accounts and passwords of the other email providers to recieve and send mails at Microsoft servers for you and then, after processing them, send them to you in your new Outlook. Classic Outlook and any other email client app not. And if i have a source for this is simply, try it or search ALL reviews of the new Outlook.