Just upgraded to F15 alpha using preupgrade. On starting evolution I get a message about migrating to maildir format, I click ok. Then evolution starts. I have no e-mail any more. It's all gone.
I'm an idiot. I apologise. The Fedora upgrade does not preserve the icons in the taskbar and add them to favourites in the gnome shell, therefore clicking the email icon will load evolution (which I no longer use) instead of thunderbird (which I do use). So no e-mail is missing, and everything is fine. Except maybe the favourites should be preserved..