When the minor version of the payload schema changes, only optional fields (example: qx) are added to an object and only new alternative objects are added.
Many fields are not formally required, because they have been added after V1.1.0, but newer versions of the connectors shall support them (e.g. pubTopic, hashVersion, qx).
Some parts of the API spec are marked as deprecated (e.g. encoding numbers as strings). New connectors shall not use any deprecated fields and existing ones shall consider to remove them in newer releases.
The “v1” as major version in the topic name means we could add a new version “v2” in parallel but the effort of doing this is too high, so we do everything to avoid that. The performance of notifying all values twice would also be very bad.