{
  "schema_version": "1.7.0",
  "id": "x_SHAPI-xero-allocations-contact-mismatch-rejected",
  "modified": "2026-10-31T01:34:50Z",
  "published": "2026-10-08T00:00:00Z",
  "summary": "Allocations between documents of different contacts are rejected",
  "details": "Xero is beginning to require (notice of 2026-10-08) a credit note, prepayment or overpayment to belong to the same contact as the invoice or bill it is allocated to. Allocation requests that create a new contact mismatch return a validation error (HTTP 400). The notice is dated 2026-10-08 and gives no separate enforcement date.\n\nBefore calling PUT /CreditNotes/{CreditNoteID}/Allocations, /Prepayments/{PrepaymentID}/Allocations or /Overpayments/{OverpaymentID}/Allocations, check that Contact.ContactID is the same on the source document and on the target invoice or bill. On a validation error, show the user the mismatch instead of retrying, because the unchanged request keeps failing.",
  "affected": [
    {
      "ecosystem_specific": {
        "provider": "xero",
        "endpoint": {
          "method": "PUT",
          "path": "/api.xro/2.0/*/{id}/Allocations"
        },
        "change_class": "status-code",
        "trigger": {
          "any": true
        },
        "effective_date": "2026-10-08"
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://developer.xero.com/changelog"
    },
    {
      "type": "WEB",
      "url": "https://raw.githubusercontent.com/XeroAPI/Xero-OpenAPI/master/xero_accounting.yaml"
    }
  ],
  "database_specific": {
    "severity": "medium",
    "status": "verified",
    "url": "https://shapi.dev/osv/xero-allocations-contact-mismatch-rejected.json"
  }
}