WARNING: using attachment_dir with plugin zlib can corrupt mails

[telsch]

>
> Actually the mail isn't saved corrupted. The bug is when reading the
> mail. So any existing corrupted mails become fixed after upgrading.
>
> Fix here:
> https://github.com/dovecot/core/commit/5068b11e594ad7cc1f7cedf2bd9280520e0e534d
>

Could this also apply to this Timo? We also using attachment_dir with
plugin zlib

https://dovecot.org/list/dovecot/2019-September/117007.html