application_identifier changed type

What changed

Serialization mismatch. Integer-to-string moves are the usual cause and the usual outage.

Affects CardPaymentDetails reachable from 6 operations.

null|string → string

Who is affected

Code that sends Square's CardPaymentDetails objects, used by 6 Square operations.

Before and after

Code that breaks

// payload.application_identifier
// was: null|string
// now: string

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