Enterprises will control which version of Outlook they deploy up to the point, in a few years from now, classic Outlook is EOL'ed for EXO. Until that point in t

Enterprises will control which version of Outlook they deploy up to the point, in a few years from now, classic Outlook is EOL'ed for EXO. Until that point in time, Microsoft can set whatever default they want, and enterprises will deploy whatever they want to.