Hi, if you try to reply to this message in notmuch (Emacs UI), you will see something like: Subject: Re: Non-ASCII characters in headers =?iso-8859-2?b?KOm56Pi+/eHt6Sk=?= To: Michal Sojka z =?iso-8859-2?b?6GVza2E=?= <sojkam1 at fel.cvut.cz>, I've tried to write a fix for this, which I send as a reply to this mail. Michal