5.3.2

New

• A provider can name a test address. A transport plugin's provider class may now have testRecipient(): ?string, answering an address the provider's own documentation names as accepted, delivered to nobody and reported back as delivered, such as Resend's delivered@resend.dev or the SES mailbox simulator. A store testing its delivery webhook sends there, so the test reaches no real inbox and still produces the event it waits for. It is deliberately not on the Provider interface, because a new interface method would be a fatal error in every transport plugin not updated in the same release: consumers ask method_exists(), a plugin that has it still loads beside an older Email plugin, and a plugin without it simply has none. Written up in docs/providers.md, with the rule that only an address the provider documents counts