On August 26, 2026 OpenAI turns off the Assistants API. /v1/assistants , /v1/threads , and /v1/threads/runs start returning errors that day. There's no grace period and no degraded mode, and OpenAI has said it won't ship a migration tool. Threads don't move over automatically either, so any conversation state you kept server-side is something you have to plan around, not port with a flag. If your code still calls openai.beta.assistants or openai.beta.threads , this is the migration. ...