I very much agree on what Joe is saying, let's use the version field as intended and be very strict with not removing nor altering existing behaviour without bumping the version. Old API versions could be deprecated (documentation only?) immediately and removed completely in the next minor version bump (0.8->0.9).
An API to query supported API versions would be a good addition in the long run but doesn't help current clients much as such a request to an older broker version will kill the connection without any error reporting to the client, thus making it rather useless in the short term. Regards, Magnus
