That's the part of NoSQL I've never understood. With a "normal" SQL DB my app has to be able to migrate between versions of data, but the code ever only support

That's the part of NoSQL I've never understood. With a "normal" SQL DB my app has to be able to migrate between versions of data, but the code ever only supports the current version. With NoSQL, you will either have to support every possible version (which might be unique per entry), or implement migrations yourself. How is that not strictly worse?