Ollama 0.40.2, released October 8, documents background upgrades of older models for llama.cpp compatibility, with original copies retained for downgrades. Removing those backups means models must be downloaded again when returning to versions before 0.40.
The patch fixes duplicate entries in ollama list and lets Claude launches use the model's full context length. This describes the October 8 release: the later 0.40.3 patch paused background migration. See the 0.40.2 notes and subsequent change.