Any issues with dsync between 2.1.7 and 2.2.9 ?

My current production system is running dovecot 2.1.7-7ubuntu1 on Ubuntu 13.04, and I'm building a new setup based on Ubuntu 14.04 with dovecot 2.2.9-1ubuntu2.1 - current standard in the repos. I'd like to use replication to get the mailstore from the old system to the new. Are there any caveats or gotchas to be aware of ?

Is it possible to make it a one-way replication ? So problems or glitches on the new setup don't propagate to the old production ?

Thanks -

D.