THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
When a replica receives a LeaderAndIsrRequest containing a topic ID for an existing partition which does not have a topic ID associated, it will create a partition metadata file for the topic partition locally. At this point the local partition will have been migrated to support topic IDs.
Changes to the directory structure should coincide with a major release since the changes will make downgrades no longer possible.
Compatibility, Deprecation, and Migration Plan
...