Timo confirmed this type of message (see below) breaks iOS mail clients regardless of the IMAP server used. So it is almost certainly a client issue.
We are in contact with the Apple Mail developers and have provided this debug information to them. michael > On 02/10/2025 7:19 AM MST Timo Sirainen via dovecot <dovecot@dovecot.org> > wrote: > > > On 10. Feb 2025, at 15.24, Florian Effenberger via dovecot > <dovecot@dovecot.org> wrote: > > > > Hello, > > > > frido--- via dovecot wrote on 10.02.25 at 14:07: > >> The problem as described at the start of this thread is not solved in iOS > >> 18.3. A bit more testing shows that it only appears to happen with > >> attachments around 1MB and bigger. > > > > there seem to be two kind of problems, at least on my devices. > > I'm also wondering if there are multiple issues. I have one way of easily > reproducing, but it has nothing to do with IMAP IDLE. Here's a test email > which causes the hang - snipped it a bit in the middle which you can fill out > yourself with: > > dd if=/dev/urandom bs=1024 count=3432 | base64 -w76 > > If you want to test multiple times, change Message-Id for every delivery. > This mail can be simply saved to INBOX, e.g. with doveadm save: > > To: <u...@example.com> > Subject: testing > Content-Type: multipart/mixed; boundary="foo" > Date: Tue, 17 Dec 2024 06:46:17 +0000 > From: <u...@example.com> > Message-Id: <fo...@example.com> > > > > --foo > Content-Type: multipart/alternative; boundary="bar" > > --bar > Content-Transfer-Encoding: quoted-printable > Content-Type: text/html; charset=UTF-8 > > asdf > --bar-- > > --foo > Content-Description: test.pdf > Content-Disposition: attachment; filename="test.pdf" > Content-Transfer-Encoding: base64 > Content-Type: application/octet-stream; name="test.pdf" > > > lBjZO0luFuyUiOqQ8KPTTpMyPoNhlSTPPJauDuCVSwbZgaNyhnObul5qrdyPKo0NGiQKA3Kha34A > <61642 lines of random> > 4cNyk39T2wMsnQavfl8LXwG1vNQylpgmSN4p6fOpmGqQ > > --foo-- > > _______________________________________________ > dovecot mailing list -- dovecot@dovecot.org > To unsubscribe send an email to dovecot-le...@dovecot.org _______________________________________________ dovecot mailing list -- dovecot@dovecot.org To unsubscribe send an email to dovecot-le...@dovecot.org
