Update: So the encoding issue seems to be at a "lower level" than mu in fact. I noticed that new messages come through with the correct encoding now, so I assume it was an (odd) issue of locale settings when I initialised the mail initially/copied over old messages. (Unfortunately there does not seem to be a great way to mass re-encode messages. I can use `iconv' to convert, but it fails on messages with attachments, I think.) best,  —Ben -- '(Dr Benjamin Slade (he/him)      ((Linguistics . University of Utah) . )      `(pgp_fp: ,(21BA 2AE1 28F6 DF36 110A 0E9C A320 BBE8 2B52 EE19))        ((:official-mail . )         (:secure-mail . ))      (:website . )        "sent by mu4e 1.6.10 in Emacs 28.1.50 with org-msg on GNU Guix")