Out of curiosity. What happens if a user still has this file? Will we just ignore it, or do we crash?

I'd prefer if we could ignore it if that isn't too much work so that we can build a fresh HNSW graph later on.

I agree with this question. We don't have a conversion from the old format. Such situations are possible even if a user updates qdrant correctly (minor-by-minor version). We probably need to implement a converter and remove everything in the next minor release. Let's discuss it. To avoid spontaneously merging before the decision, I mark this PR as changes required.

Such situations are possible even if a user updates qdrant correctly (minor-by-minor version).

Good point.

Such situations are possible even if a user updates qdrant correctly (minor-by-minor version).

Good point.

I'm reading current dev and it seems we have conversion and we can merge this PR. @xzfc do you have a chance to check manually if the old format will work correctly?

The conversion happens at 0.11.1 → 1.0.0 with the following message:

[segment::segment_constructor::segment_constructor_base] Migrating segment 0.4.0 -> 0.5.0

So, this was a dead code already.