Comment 7 for bug 1545686

I don't think min-juju-version should be ignored. If it is present, the charm has declared that it is incompatible with certain juju versions, and those versions should not attempt to run it. If the jujus cannot determine whether they are compatible, it is best to assume they are incompatible. There may be some fields which are optional and can safely be ignored, but I don't think min-juju-version is one of them.