[ceph-users] Are ceph commands backward compatible?

Hi, I'm developing some tools that execute ceph commands like rbd. During development, I have come to wonder about compatibility of ceph commands. I'd like to use ceph commands which version is >= the version used by ceph daemons. It results in executing new ceph commands against ceph clusters using old versions. So I'd like to know my tools are expected to work fine. Coud someone tell me whether ceph commands are backword compatible? The officlal document didn't have the information I needed. Thanks, Satoru