# version-unknown

`https://ckrets.ai/problems/version-unknown` is a problem type of the ckrets.ai API (RFC 9457: the body is
`application/problem+json` with `type`, `title`, `status` and `detail`; every problem from `/v1` also carries `requestId`).

| Status | Also in the answer | What to do |
|---|---|---|
| 400 | - | the `Ckrets-Version` header names a date this server does not serve; `supported` (and `detail`) list the dates it does. Send one of them, or no header for the original contract |

Every type, with its retry rule and headers: [limits.md, "Errors, retries and headers"](/limits.md#errors-retries-and-headers).