* Jakobus Schürz:

> 1543935543.M447415P13997.mymail,S=726,W=748:2,Sa
>
> Then i move this email to another IMAP-Folder, and then there is the
> filename
>
> 1543935543.M447415P13997.mymail,S=726,W=748:2,
>
> As expected, the seen-flag disappeared... the same as thunderbird
> shows.

And what about the "dovecot-keywords" files in both folders? Do they
match? The letter "a" seems to indicates that there is at least one
non-standard flag defined in the source folder's keywords. By the way,
can I assume you move messages only by using Thunderbird/IMAP and not by
manipulating the file system?

Here's how things look on my server:

  # On arrival (UNSEEN)
  1543968031.M941319P5841.foo,S=1390,W=1422:2,
  # After reading (SEEN)
  1543968031.M941319P5841.foo,S=1390,W=1422:2,S
  # After being moved to another folder (SEEN)
  1543968031.M941319P5841.foo,S=1390,W=1422:2,S

I can use IMAP search terms SEEN and UNSEEN as indicated above, and I
see the same message state displayed in Notmuch mail (my default, it
accesses Dovecot's Maildir storage directly) and various IMAP clients
connecting to Dovecot. Things are working just fine here.

-Ralph