{
  "opened": "2026-10",
  "sources": [
    {
      "kind": "Wikipedia",
      "title": "Session Initiation Protocol",
      "url": "https://en.wikipedia.org/wiki/Session_Initiation_Protocol"
    },
    {
      "kind": "RFC",
      "title": "RFC 3261, SIP",
      "url": "https://www.rfc-editor.org/rfc/rfc3261"
    },
    {
      "kind": "IANA",
      "title": "IANA SIP parameters",
      "url": "https://www.iana.org/assignments/sip-parameters/sip-parameters.xhtml"
    },
    {
      "kind": "RFC",
      "title": "RFC 7092, taxonomy of SIP back-to-back user agents",
      "url": "https://www.rfc-editor.org/rfc/rfc7092"
    },
    {
      "kind": "Confirm",
      "title": "A vendor's private SIP header list. confirm. IANA says standard headers must not begin with P-, and a private list was not opened.",
      "url": null
    }
  ]
}