In Jenkins 1.653+ the protocol used by a master to communicate with its slaves is JNLP v2 or v3 (source : https://github.com/jenkinsci/jenkins/commit/b1e3f6fdd2095d17293ce2c9b26e40ea98380d73). We may imagine that in the future we may have more versions in the wild and probably it could be applied to various connectors. We should be able in bundles to know which version of protocols is used in jenkins connectors.