doveadm-sync stateful

[Cédric ML]

Hello,

I'm trying to migrate mail accounts from an old server to a new one.
As I need to migrate dozens of accounts which take about 1G each, I need 
to do stateful sync to make my migration in two times :

1 - I run a :
     doveadm -D -o mail_fsync=never -o imapc_user=user1 at olddomain.fr 
sync -s "" -R -1 -u user1 at newdomain.fr imapc: > /tmp/firstsync.log 2>&1

my accounts are synced, and I get a "state" string (AQAAAHm4+Jk=) as the 
output of doveadm sync command.

2 - Changes are made on the old server, and I expect next dsync will 
sync only the changes / new mails. So I run a :
     doveadm -D -o mail_fsync=never -o imapc_user=user1 at olddomain.fr 
sync -s "AQAAAHm4+Jk=" -R -1 -u user1 at newdomain.fr imapc: > 
/tmp/secondsync.log 2>&1


My problem is that state of messages are not synchronized (mails marked 
as read on old server are still unread on new server, mails moved on a 
folder on the old server are still in the INBOX of new server).

The full debug of ran commands is available here : 
http://fpaste.scsys.co.uk/557551
The result of "doveconf -n" is available here : 
http://fpaste.scsys.co.uk/557552
I'm using version 2.2.27

Can anyone tell me if I'm doing something wrong ? How can I debug more ?

Regards,
Cédric