countries is no longer accepted

What changed

Usually ignored rather than rejected, so the call succeeds and does something subtly different.

Affects filters.countries on POST /v1/financial_connections/sessions. Grep for it: nothing else will tell you.

Who is affected

Code that sends POST /v1/financial_connections/sessions (filters.countries).

Before and after

Code that breaks

await client.post("/v1/financial_connections/sessions", {
  // countries is now ignored, not rejected
  countries: value,
});

Based on Stripe’s published API specification. How severity is decided.