1. Introduction

Cette page resume la section correspondante du RFC 9982 et conserve les points essentiels sur JSContact, vCard et les registres IANA.

JSContact [RFC9553] defines the Card object uid property as mandatory. The vCard [RFC6350] contact format defines the UID property as optional. In this document, uid denotes the JSContact property and UID denotes the vCard property.

The mandatory JSContact uid property is useful for some cases but problematic in others. JSContact aims to be compatible with vCard semantics, but vCard makes UID optional. Synchronization protocols such as CardDAV [RFC6352] and JMAP for Contacts [RFC9610] require uid, while protocols such as RDAP [RFC9083] do not need it.

The document also explains a conversion problem: RFC 9555 required generating a unique identifier when converting vCards without UID to JSContact, but the generated value might be ephemeral and inconsistent across implementations or repeated conversions. If another Card refers to that value through members or relatedTo, invalid relations can result.