[Dovecot] dsync, a zero-way synchronisation tool?

Hi folks!

I have set up dsync replication with SSH according to http://wiki2.dovecot.org/Replication with the exception of having system users and calling doveadm dsync-server directly from authorized_keys, because the wrapper script posted on the above site is needless (at least in 2.2.10).

However, while the two instances connect well to each other, no synchronisation is performed at all, the mailboxes happily remain untouched. I've then temporarily replaced SSH with socat and captured the traffic.

Any hints what goes wrong? Unfortunately there are no logs to provide...

Greetings, Fabiano