# new_classes on PUT /client/v4/accounts/{}/workers/scripts/{} stops working

Calls to PUT /client/v4/accounts/{id}/workers/scripts/{id}, body parameter new_classes on Cloudflare API stopped working on July 9, 2026.

On July 9, 2026, Cloudflare API introduced a breaking change to PUT /client/v4/accounts/{id}/workers/scripts/{id}. Requests using the body parameter new_classes to set up key-value backed Durable Object namespaces fail if the account does not already have one. After that day, callers cannot create these namespaces using that parameter.

## What to use instead

Create Durable Object classes with a new_sqlite_classes migration instead of new_classes.

- API: Cloudflare API (api.cloudflare.com)
- Kind: Behaviour change
- Announced: July 9, 2026
- Takes effect: July 9, 2026
- Calls after that day: fail
- Calls it hits: `PUT /client/v4/accounts/{id}/workers/scripts/{id}`, `body parameter new_classes`
- Source: [Announcement](https://developers.cloudflare.com/changelog/post/2026-07-09-restrict-new-kv-backed-namespaces/)
- Verified: November 6, 2026, against Cloudflare API's own pages
- Page: https://www.okapi.bot/providers/cloudflare/breaking-changes/new-classes-on-put-client-v4-accounts-workers-scripts-stops-working/

## Cloudflare API's words

> If your account does not already have a key-value (KV) backed Durable Object namespace, you can no longer create new ones.

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent