On 2 Apr 2019, at 17.03, Jan-Pieter Cornet via dovecot <dovecot@dovecot.org> wrote:

Hi,

We're synching mailboxes, changing format from maildir to mdbox, using doveadm backup/doveadm sync.

When still running 2.2.36, 'doveadm backup' also synched the sieve scripts, without issues.

After the upgrade to 2.3.5.1, the sieve sync stopped working. We're using the pre-built 2.3 packages from https://repo.dovecot.org/ce-2.3-latest/debian/stretch

Looks like this is trivial to reproduce. It used to work still in v2.3.1, but then something broke it. Tracking internally in DOP-1062.