inspiration:

• Allow for client to provide records with newer COMPATIBLE or older (upgradable) version of schema to the server dandi-cli#1732

so that server could actually disclose which versions are Ok for it as it could potentially upgrade them (e.g. during validation).
Then client could restrict uploads to only those which are known to be migratable if version on server found to be newer than what client knows. And if it is not in the list (e.g. blacklisted or whatnot) it would fail!