since they didnt rev the version, does this mean if we were using 3.5 today its just automatically using the new version? That doesnt seem great from a change management perspective

though I am looking forward to using the new one in cursor.ai

No, Claude's models use date-pinning. The new model endpoint is claude-3-5-sonnet-20241022

https://docs.anthropic.com/en/docs/about-claude/models