What changed
No action needed unless you validate responses against a closed schema.
Affects POST /v1/billing/buy.
Who is affected
Code that reads POST /v1/billing/buy (purchaseIntent.configuration.options.fromPlan.additionalSubscriptions).
Before and after
| Where | Before | After |
|---|---|---|
| POST /v1/billing/buy · purchaseIntent.configuration.options.fromPlan.additionalSubscriptions | absent | present |
Based on Vercel’s published API specification. How severity is decided.