Follow-up to my first answer: Yesterday, I happened to look into app-store. And behold: there was an update for k9. It must be quite new; as it is only a few days ago where I got my new mobile and did the original downloads.
So: first thing: get this update. Best regards Günter -- You received this message because you are subscribed to the Google Groups "K-9 Mail" group. To unsubscribe from this group and stop receiving emails from it, send an email to k-9-mail+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.