Charge-Version header.
cURL
api_version on that Webhook Endpoint. If you leave it unset, the endpoint uses the account default version.
Each Event stores the api_version that was used to render its payload when the event was created. Treat events as snapshots: changing your account default later does not rewrite older event payloads.
When you upgrade, test the target version first and move webhook consumers deliberately. In most cases, the right approach is to keep using the account default and pin a version only when you need controlled rollout for a specific endpoint.
