question about v2

Hi, I find that you mention the model is re-trained. I wonder if the old checkpoint is still compatible with v2 implementation? thanks！

The issue mentions the v2 implementation and an old checkpoint; begin by checking how v2 handles checkpoint loading and compatibility. Done means confirming whether the old checkpoint works with v2 and recording the answer in the issue or relevant documentation.

Written by the indexing model from the issue text.