Schema draft mismatch: definitions versus $defs, draft 2019-09 versus 2020-12
Symptom
The validator reports 'can't resolve reference' or 'no schema with key or ref' when loading the schema, before the message is tested.
Cause
Release 2027 migrated to JSON Schema draft 2020-12 ($defs, https references); Release 2026 uses draft 2019-09 with definitions. In addition the schemas refer to external code lists on sivi.org that the validator must know.
Fix
Use a validator that supports both drafts (AJV: Ajv2019 and Ajv2020) and register the code lists from the afdCodelists files under the URL the schema uses; the WTP Data Lab validator does this automatically.
Check your own message for this and all other errors with the free validator: schema, code lists and consistency checks in one report.Validate a message
Attribution. Source: SIVI – VB-PUO Standard. Schemas, attribute descriptions and code lists are taken unchanged from the VB-PUO Standard (owned by the Pensioenfederatie, managed by SIVI) and shown with their release and version. Explanations, examples, error descriptions and translations are by WTP Data Lab and are not part of the standard. GitHub Stichting-SIVI/VBPUOdsk · Manual · sivi.org
