What changed
Producer-side tools call this non-breaking. For a consumer it is a null dereference on an unknown future date.
Affects services[].builder.config.daemon.replicas on PATCH /v12/deployments/{id}/cancel. Nothing fails at the call; it fails wherever the value is finally used, which is usually somewhere else entirely.
no longer guaranteed present
Who is affected
Code that reads PATCH /v12/deployments/{id}/cancel (services[].builder.config.daemon.replicas).
Before and after
| Where | Before | After |
|---|---|---|
| PATCH /v12/deployments/{id}/cancel · services[].builder.config.daemon.replicas | always present | may be missing |
| POST /v13/deployments · services[].builder.config.daemon.replicas | always present | may be missing |
| GET /v13/deployments/{idOrUrl} · services[].builder.config.daemon.replicas | always present | may be missing |
Code that breaks
// response.services[0].builder.config.daemon.replicas may now be absent or null const replicas = response.services[0].builder.config.daemon.replicas ?? fallback;
Based on Vercel’s published API specification. How severity is decided.