{
  "id": "ucp.version.pin",
  "protocol": "ucp",
  "layer": "foundation",
  "role": "platform",
  "status": "required",
  "title": "Declare a dated release in ucp.version",
  "description": "UCP uses date-based versions (YYYY-MM-DD). The profile declares one version; older ones go in supported_versions.",
  "goal": "Version selection and capability matching depend on it. A wrong value breaks negotiation.",
  "note": "Resolved: the spec says the version MUST be a dated release and MUST NOT be a non-date string such as draft. Releases on GitHub: 2026-01-11, 2026-01-23, 2026-04-08, 2026-08-25.",
  "how_to_implement": {
    "steps": [
      "Set ucp.version to the dated release you implement.",
      "Optionally map older releases to full profiles in supported_versions.",
      "Never publish pre-release implementations through public discovery."
    ]
  },
  "resources": [
    {
      "label": "UCP spec overview (latest): versioning and hosting",
      "url": "https://ucp.dev/latest/specification/overview/",
      "type": "spec",
      "publisher": "UCP"
    },
    {
      "label": "UCP releases on GitHub",
      "url": "https://github.com/Universal-Commerce-Protocol/ucp/releases",
      "type": "spec",
      "publisher": "UCP"
    }
  ],
  "audit": {
    "method": "http_get",
    "automatable": true,
    "url_pattern": "/.well-known/ucp",
    "expect": {
      "status": 200,
      "json_keys": [
        "ucp.version"
      ],
      "json_pattern": {
        "ucp.version": "^\\d{4}-\\d{2}-\\d{2}$"
      }
    },
    "human": "ucp.version matches ^\\d{4}-\\d{2}-\\d{2}$ and equals a published release."
  },
  "how_to_verify": "ucp.version matches ^\\d{4}-\\d{2}-\\d{2}$ and equals a published release.",
  "artifacts": [
    "ucp.version",
    "supported_versions"
  ],
  "depends_on": [
    "ucp.discovery.well-known"
  ],
  "status_note": "Resolved: the spec says the version MUST be a dated release and MUST NOT be a non-date string such as draft. Releases on GitHub: 2026-01-11, 2026-01-23, 2026-04-08, 2026-08-25.",
  "verified": true,
  "slug": "ucp-version-pin",
  "category": "foundation",
  "url": "https://vreeman.ai/commerce/checklist#ucp.version.pin",
  "updated": "2026-10-12",
  "sources": [
    {
      "label": "UCP spec overview (latest): versioning and hosting",
      "url": "https://ucp.dev/latest/specification/overview/",
      "type": "spec",
      "publisher": "UCP"
    },
    {
      "label": "UCP releases on GitHub",
      "url": "https://github.com/Universal-Commerce-Protocol/ucp/releases",
      "type": "spec",
      "publisher": "UCP"
    }
  ],
  "related_slugs": [
    "ucp-discovery-well-known"
  ]
}