Authoritative source
`docs/API_SOURCE_VERSIONING.md` identifies Digital Trusted Identity Service API And Kafka Specifications V1.2.260123 as the current source of truth and states that it supersedes AWS Signature documentation.
LEGACY · SUPERSEDED
AWS Signature historical documentation
CheckID API contract V1.2.260123 replaced legacy AWS Signature guidance with OAuth2 Client Credentials + Bearer authorization.
TECHNICAL REFERENCE
Migration boundary
Legacy signing → current OAuth2 Client Credentials
Current authentication
The current API catalog uses the OAuth2 Client Credentials token endpoint and Bearer access tokens for partner operations.
No “AWS ” contract
The v8 baseline displayed “AWS Signature ”; no primary source in the ZIP defines such a mechanism. Current documentation removes that wording rather than preserving false ambiguity.
Migration
New integrations must follow the current Authentication/Quickstart guidance. Legacy remains only as a historical boundary notice, not production guidance.
Security
Do not embed client secrets in browsers/mobile clients. Credential issuance/rotation and network controls remain partner-onboarding/deployment concerns.
Compatibility
If a legacy customer still uses , migration window and backward compatibility require API-owner/contract confirmation; the site does not invent a sunset date.