Maybe. Any time we ask a library or client to do HTTP fetches when it historically only did SMTP I become less optimistic about adoption. There are obvious ea

Maybe. Any time we ask a library or client to do HTTP fetches when it historically only did SMTP I become less optimistic about adoption. There are obvious easy wins like Thunderbird and Outlook and those could potentially use a plugin or add-on. Maybe that could be a good start and good enough.