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Internet Engineering Task Force (IETF) N. Jenkins, Ed.
Request for Comments: 9610 Fastmail
Category: Standards Track December 2024
ISSN: 2070-1721
JSON Meta Application Protocol (JMAP) for Contacts
Abstract
This document specifies a data model for synchronising contact data
with a server using the JSON Meta Application Protocol (JMAP).
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9610.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Introduction
1.1. Notational Conventions
1.2. Terminology
1.3. Data Model Overview
1.4. Addition to the Capabilities Object
1.4.1. urn:ietf:params:jmap:contacts
2. AddressBooks
2.1. AddressBook/get
2.2. AddressBook/changes
2.3. AddressBook/set
3. ContactCards
3.1. ContactCard/get
3.2. ContactCard/changes
3.3. ContactCard/query
3.3.1. Filtering
3.3.2. Sorting
3.4. ContactCard/queryChanges
3.5. ContactCard/set
3.6. ContactCard/copy
4. Examples
4.1. Fetching Initial Data
4.2. Changing the Default Address Book
5. Internationalisation Considerations
6. Security Considerations
7. IANA Considerations
7.1. JMAP Capability Registration for "contacts"
7.2. JMAP Data Type Registration for "AddressBook"
7.3. JMAP Data Type Registration for "ContactCard"
7.4. JMAP Error Codes Registry
7.4.1. addressBookHasContents
7.5. JSContact Property Registrations
7.5.1. id
7.5.2. addressBookIds
7.5.3. blobId
8. References
8.1. Normative References
8.2. Informative References
Author's Address
1. Introduction
The JSON Meta Application Protocol (JMAP) [RFC8620] is a generic
protocol for synchronising data, such as mail, calendars, or
contacts, between a client and a server. It is optimised for mobile
and web environments and aims to provide a consistent interface to
different data types.
This specification defines a data model for synchronising contacts
between a client and a server using JMAP.
1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Type signatures, examples, and property descriptions in this document
follow the conventions established in Section 1.1 of [RFC8620]. The
Id, UnsignedInt, and UTCDate data types defined in Sections 1.2, 1.3,
and 1.4 of [RFC8620] are also used in this document.
1.2. Terminology
The same terminology used in the core JMAP specification (see
Section 1.6 of [RFC8620]) is also used in this document.
The terms AddressBook and ContactCard (with these specific
capitalizations) are used to refer to the data types defined in this
document and instances of those data types.
1.3. Data Model Overview
An Account (see Section 1.6.2 of [RFC8620]) with support for the
contact data model contains zero or more AddressBook objects, which
is a named collection of zero or more ContactCards. A ContactCard is
a representation of a person, company, entity, or a group of such
entities in JSContact Card format, as defined in Section 2 of
[RFC9553]. Each ContactCard belongs to one or more AddressBooks.
In servers with support for JMAP Sharing [RFC9670], users may see and
configure sharing of contact data with others. Sharing permissions
are managed per AddressBook.
1.4. Addition to the Capabilities Object
The capabilities object is returned as part of the JMAP Session
object; see Section 2 of [RFC8620]. This document defines one
additional capability URI.
1.4.1. urn:ietf:params:jmap:contacts
This represents support for the AddressBook and ContactCard data
types and associated API methods. The value of this property in the
JMAP Session "capabilities" property is an empty object.
The value of this property in an account's "accountCapabilities"
property is an object that MUST contain the following information on
server capabilities and permissions for that account:
*maxAddressBooksPerCard*: UnsignedInt|null
The maximum number of AddressBooks (see Section 2) that can be
assigned to a single ContactCard object (see Section 3). This
MUST be an integer >= 1, or null for no limit (or rather, the
limit is always the number of AddressBooks in the account).
*mayCreateAddressBook*: Boolean
The user may create an AddressBook in this account if, and only
if, this is true.
2. AddressBooks
An AddressBook is a named collection of ContactCards. All
ContactCards are associated with one or more AddressBooks.
An *AddressBook* object has the following properties:
*id*: Id (immutable; server-set)
The id of the AddressBook.
*name*: String
The user-visible name of the AddressBook. This MUST NOT be the
empty string and MUST NOT be greater than 255 octets in size when
encoded as UTF-8.
*description*: String|null (default: null)
An optional long-form description of the AddressBook that provides
context in shared environments where users need more than just the
name.
*sortOrder*: UnsignedInt (default: 0)
Defines the sort order of AddressBooks when presented in the
client's UI so it is consistent between devices. The number MUST
be an integer in the range 0 <= sortOrder < 2^31.
An AddressBook with a lower order is to be displayed before a
AddressBook with a higher order in any list of AddressBooks in the
client's UI. AddressBooks with equal order should be sorted in
alphabetical order by name. The sorting should take into account
locale-specific character order convention.
*isDefault*: Boolean (server-set)
This SHOULD be true for exactly one AddressBook in any account and
MUST NOT be true for more than one AddressBook within an account.
The default AddressBook should be used by clients whenever they
need to choose an AddressBook for the user within this account and
they do not have any other information on which to make a choice.
For example, if the user creates a new contact card, the client
may automatically set the card as belonging to the default
AddressBook from the user's primary account.
*isSubscribed*: Boolean
True if the user has indicated they wish to see this AddressBook
in their client. This SHOULD default to false for AddressBooks in
shared accounts that the user has access to and true for any new
AddressBooks created by the user themself.
If false, the AddressBook and its contents SHOULD only be
displayed when the user explicitly requests it. The UI may offer
to the user the option of subscribing to it.
*shareWith*: Id[AddressBookRights]|null (default: null)
A map of the Principal id (Section 2 of [RFC9670]) to rights for
Principals this AddressBook is shared with. The Principal to
which this AddressBook belongs MUST NOT be in this set. This is
null if the AddressBook is not shared with anyone or if the server
does not support [RFC9670]. The value may be modified only if the
user has the "mayShare" right. The account id for the Principals
may be found in the urn:ietf:params:jmap:principals:owner
capability of the Account to which the AddressBook belongs.
*myRights*: AddressBookRights (server-set)
The set of access rights the user has in relation to this
AddressBook.
An *AddressBookRights* object has the following properties:
*mayRead*: Boolean
The user may fetch the ContactCards in this AddressBook.
*mayWrite*: Boolean
The user may create, modify, or destroy all ContactCards in this
AddressBook, or move them to or from this AddressBook.
*mayShare*: Boolean
The user may modify the "shareWith" property for this AddressBook.
*mayDelete*: Boolean
The user may delete the AddressBook itself.
2.1. AddressBook/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620]. The "ids" argument may be null to fetch all at once.
2.2. AddressBook/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
2.3. AddressBook/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620], but with the following additional request arguments:
*onDestroyRemoveContents*: Boolean (default: false)
If false, any attempt to destroy an AddressBook that still has a
ContactCard in it will be rejected with an
"addressBookHasContents" SetError. If true, any ContactCard that
is in the AddressBook will be removed from it, and if such a
ContactCard does not belong to any other AddressBook, it will be
destroyed.
*onSuccessSetIsDefault*: Id|null
If an id is given, and all creates, updates, and destroys (if any)
succeed without error, the server will try to set this AddressBook
as the default. (For references to AddressBook creations, this is
equivalent to a creation-reference, so the id will be the creation
id prefixed with a "#".)
If the id is not found or if the change is not permitted by the
server for policy reasons, it MUST be ignored and the current default
AddressBook (if any) will remain as such. No error is returned to
the client in this case.
As per Section 5.3 of [RFC8620], if the default AddressBook is
successfully changed, any changed objects MUST be reported in either
the "created" or "updated" argument in the response as appropriate,
with the server-set value included.
The "shareWith" property may only be set by users that have the
"mayShare" right. When modifying the "shareWith" property, the user
cannot give a right to a Principal if the Principal did not already
have that right and the user making the change also does not have
that right. Any attempt to do so MUST be rejected with a "forbidden"
SetError.
Users can subscribe or unsubscribe to an AddressBook by setting the
"isSubscribed" property. The server MAY forbid users from
subscribing to certain AddressBooks even though they have permission
to see them, rejecting the update with a "forbidden" SetError.
The following extra SetError type is defined for "destroy":
*addressBookHasContents*: The AddressBook has at least one
ContactCard assigned to it and the "onDestroyRemoveContents"
argument was false.
3. ContactCards
A *ContactCard* object contains information about a person, company,
or other entity, or represents a group of such entities. It is a
JSContact Card object as defined in Section 2 of [RFC9553] with the
following additional properties:
*id*: Id (immutable; server-set)
The id of the ContactCard. The "id" property MAY be different to
the ContactCard's "uid" property (as defined in Section 2.1.9 of
[RFC9553]). However, there MUST NOT be more than one ContactCard
with the same uid in an Account.
*addressBookIds*: Id[Boolean]
The set of AddressBook ids that this ContactCard belongs to. A
card MUST belong to at least one AddressBook at all times (until
it is destroyed). The set is represented as an object, with each
key being an AddressBook id. The value for each key in the object
MUST be true.
For any Media object in the card (see Section 2.6.4 of [RFC9553]), a
new property is defined:
*blobId*: Id
An id for the Blob representing the binary contents of the
resource.
When returning ContactCards, any Media with a URI that uses the
"data:" URL scheme [RFC2397] SHOULD return a "blobId" property and
omit the "uri" property, as this lets clients load the (potentially
large) image file only when needed and avoids the overhead of Base64
encoding. The "mediaType" property MUST also be set. Similarly,
when creating or updating a ContactCard, clients MAY send a "blobId"
instead of the "uri" property for a Media object.
A contact card with a "kind" property equal to "group" represents a
group of contacts. Clients often present these separately from other
contact cards. The "members" property, as defined in Section 2.1.6
of [RFC9553], contains a set of uids (as defined in Section 2.1.9 of
[RFC9553]) for other contacts that are the members of this group.
Clients should consider the group to contain any ContactCard with a
matching uid from any account they have access to that has support
for the urn:ietf:params:jmap:contacts capability. Any uid that
cannot be found SHOULD be ignored but preserved. For example,
suppose a user adds contacts from a shared address book to their
private group, then temporarily loses access to this address book.
The uids cannot be resolved, so the contacts will disappear from the
group. However, if they are given permission to access the data
again, the uids will be found and the contacts will reappear.
3.1. ContactCard/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620].
3.2. ContactCard/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
3.3. ContactCard/query
This is a standard "/query" method as described in Section 5.5 of
[RFC8620].
3.3.1. Filtering
A *FilterCondition* object has the following properties, any of which
may be omitted:
*inAddressBook*: Id
An AddressBook id. A card must be in this address book to match
the condition.
*uid*: String
A card must have this string exactly as its uid (as defined in
Section 2.1.9 of [RFC9553]) to match.
*hasMember*: String
A card must have a "members" property (as defined in Section 2.1.6
of [RFC9553]) that contains this string as one of the uids in the
set to match.
*kind*: String
A card must have a "kind" property (as defined in Section 2.1.4 of
[RFC9553]) that equals this string exactly to match.
*createdBefore*: UTCDate
The "created" date-time of the ContactCard (as defined in
Section 2.1.3 of [RFC9553]) must be before this date-time to match
the condition.
*createdAfter*: UTCDate
The "created" date-time of the ContactCard (as defined in
Section 2.1.3 of [RFC9553]) must be the same or after this date-
time to match the condition.
*updatedBefore*: UTCDate
The "updated" date-time of the ContactCard (as defined in
Section 2.1.10 of [RFC9553]) must be before this date-time to
match the condition.
*updatedAfter*: UTCDate
The "updated" date-time of the ContactCard (as defined in
Section 2.1.10 of [RFC9553]) must be the same or after this date-
time to match the condition.
*text*: String
A card matches this condition if the text matches with text in the
card.
*name*: String
A card matches this condition if the value of any NameComponent in
the "name" property or the "full" property in the "name" property
of the card (as defined in Section 2.2.1.2 of [RFC9553]) matches
the value.
*name/given*: String
A card matches this condition if the value of a NameComponent with
kind "given" inside the "name" property of the card (as defined in
Section 2.2.1.2 of [RFC9553]) matches the value.
*name/surname*: String
A card matches this condition if the value of a NameComponent with
kind "surname" inside the "name" property of the card (as defined
in Section 2.2.1.2 of [RFC9553]) matches the value.
*name/surname2*: String
A card matches this condition if the value of a NameComponent with
kind "surname2" inside the "name" property of the card (as defined
in Section 2.2.1.2 of [RFC9553]) matches the value.
*nickname*: String
A card matches this condition if the "name" of any Nickname in the
"nicknames" property of the card (as defined in Section 2.2.2 of
[RFC9553]) matches the value.
*organization*: String
A card matches this condition if the "name" of any Organization in
the "organizations" property of the card (as defined in
Section 2.2.3 of [RFC9553]) matches the value.
*email*: String
A card matches this condition if the "address" or "label" of any
EmailAddress in the "emails" property of the card (as defined in
Section 2.3.1 of [RFC9553]) matches the value.
*phone*: String
A card matches this condition if the "number" or "label" of any
Phone in the "phones" property of the card (as defined in
Section 2.3.3 of [RFC9553]) matches the value.
*onlineService*: String
A card matches this condition if the "service", "uri", "user", or
"label" of any OnlineService in the "onlineServices" property of
the card (as defined in Section 2.3.2 of [RFC9553]) matches the
value.
*address*: String
A card matches this condition if the value of any AddressComponent
in the "addresses" property or the "full" property in the
"addresses" property of the card (as defined in Section 2.5.1 of
[RFC9553]) matches the value.
*note*: String
A card matches this condition if the "note" of any Note in the
"notes" property of the card (as defined in Section 2.8.3 of
[RFC9553]) matches the value.
If zero properties are specified on the FilterCondition, the
condition MUST always evaluate to true. If multiple properties are
specified, ALL must apply for the condition to be true (it is
equivalent to splitting the object into one-property conditions and
making them all the child of an AND filter operator).
The exact semantics for matching String fields is deliberately not
defined to allow for flexibility in indexing implementation, subject
to the following:
* Text SHOULD be matched in a case-insensitive manner.
* Text contained in either (but matched) single or double quotes
SHOULD be treated as a phrase search. That is, a match is
required for that exact sequence of words, excluding the
surrounding quotation marks. Use \", \', and \\ to match a
literal ", ', and \ respectively in a phrase.
* Outside of a phrase, whitespace SHOULD be treated as dividing
separate tokens that may be searched for separately in the
contact, but MUST all be present for the contact to match the
filter.
* Tokens MAY be matched on a whole-word basis using stemming (e.g.,
a text search for bus would match "buses", but not "business").
3.3.2. Sorting
The following values for the "property" field on the Comparator
object MUST be supported for sorting:
* "created" - The "created" date on the ContactCard.
* "updated" - The "updated" date on the ContactCard.
The following values for the "property" field on the Comparator
object SHOULD be supported for sorting:
* "name/given" - The value of the first NameComponent in the "name"
property whose "kind" is "given".
* "name/surname" - The value of the first NameComponent in the
"name" property whose "kind" is "surname".
* "name/surname2" - The value of the first NameComponent in the
"name" property whose "kind" is "surname2".
3.4. ContactCard/queryChanges
This is a standard "/queryChanges" method as described in Section 5.6
of [RFC8620].
3.5. ContactCard/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620].
To set a new photo, the file must first be uploaded using the upload
mechanism as described in Section 6.1 of [RFC8620]. This will give
the client a valid blobId, size, and type to use. The server MUST
reject attempts to set a file that is not a recognised image type as
the photo for a card.
3.6. ContactCard/copy
This is a standard "/copy" method as described in Section 5.4 of
[RFC8620].
4. Examples
For brevity, only the "methodCalls" property of the Request object
and the "methodResponses" property of the Response object is shown in
the following examples.
4.1. Fetching Initial Data
A user has authenticated and the client has fetched the JMAP Session
object. It finds a single Account with the
"urn:ietf:params:jmap:contacts" capability with id "a0x9" and wants
to fetch all the address books and contacts. It might make the
following request:
[
["AddressBook/get", {
"accountId": "a0x9"
}, "0"],
["ContactCard/get", {
"accountId": "a0x9"
}, "1"]
]
Figure 1: "methodCalls" Property of a JMAP Request
The server might respond with something like:
[
["AddressBook/get", {
"accountId": "a0x9",
"list": [{
"id": "062adcfa-105d-455c-bc60-6db68b69c3f3",
"name": "Personal",
"description": null,
"sortOrder": 0,
"isDefault": true,
"isSubscribed": true,
"shareWith": {
"3f1502e0-63fe-4335-9ff3-e739c188f5dd": {
"mayRead": true,
"mayWrite": false,
"mayShare": false,
"mayDelete": false
}
},
"myRights": {
"mayRead": true,
"mayWrite": true,
"mayShare": true,
"mayDelete": false
}
}, {
"id": "cd40089d-35f9-4fd7-980b-ba3a9f1d74fe",
"name": "Autosaved",
"description": null,
"sortOrder": 1,
"isDefault": false,
"isSubscribed": true,
"shareWith": null,
"myRights": {
"mayRead": true,
"mayWrite": true,
"mayShare": true,
"mayDelete": false
}
}],
"notFound": [],
"state": "~4144"
}, "0"],
["ContactCard/get", {
"accountId": "a0x9",
"list": [{
"id": "3",
"addressBookIds": {
"062adcfa-105d-455c-bc60-6db68b69c3f3": true
},
"name": {
"components": [
{ "kind": "given", "value": "Joe" },
{ "kind": "surname", "value": "Bloggs" }
],
"isOrdered": true
},
"emails": {
"0": {
"contexts": {
"private": true
},
"address": "joe.bloggs@example.com"
}
}
}],
"notFound": [],
"state": "ewarbckaqJ::112"
}, "1"]
]
Figure 2: "methodResponses" Property of a JMAP Response
4.2. Changing the Default Address Book
The client tries to change the default address book from "Personal"
to "Autosaved" (and makes no other change):
[
["AddressBook/set", {
"accountId": "a0x9",
"onSuccessSetIsDefault": "cd40089d-35f9-4fd7-980b-ba3a9f1d74fe"
}, "0"]
]
Figure 3: "methodCalls" Property of a JMAP Request
The server allows the change, returning the following response:
[
["AddressBook/set", {
"accountId": "a0x9",
"updated": {
"cd40089d-35f9-4fd7-980b-ba3a9f1d74fe": {
"isDefault": true
},
"062adcfa-105d-455c-bc60-6db68b69c3f3": {
"isDefault": false
},
"oldState": "~4144",
"newState": "~4148"
}
}, "0"]
]
Figure 4: "methodResponses" Property of a JMAP Response
5. Internationalisation Considerations
Experience has shown that unrestricted use of Unicode can lead to
problems such as inconsistent rendering, users reading text and
interpreting it differently than intended, and unexpected results
when copying text from one location to another. Servers MAY choose
to mitigate this by restricting the set of characters allowed in
otherwise unconstrained String fields. The FreeformClass, as
documented in Section 4.3 of [RFC8264], might be a good starting
point for this.
Attempts to set a value containing code points outside of the
permissible set can be handled in a few ways by the server. The
server could choose to strip the forbidden characters or replace them
with U+FFFD (the Unicode replacement character) and store the
resulting string. This is likely to be appropriate for non-printable
characters -- such as the "Control Codes" defined in Section 23.1
(https://www.unicode.org/versions/latest/core-spec/chapter-
23/#G20365) of [UNICODE], excluding newline (U+000A), carriage return
(U+000D), and tab (U+0009) -- that can end up in data accidentally
due to copy-and-paste issues but are invisible to the end user. JMAP
allows the server to transform data on create/update as long as any
changed properties are returned to the client in the "/set" response
so it knows what has changed, as per Section 5.3 of [RFC8620].
Alternatively, the server MAY just reject the create/update with an
"invalidProperties" SetError.
6. Security Considerations
All security considerations of JMAP [RFC8620] apply to this
specification. Additional considerations specific to the data types
and functionality introduced by this document are described in the
following subsection.
Contacts consist almost entirely of private, personally identifiable
information, and represent the social connections of users. Privacy
leaks can have real world consequences, and contact servers and
clients MUST be mindful of the need to keep all data secure.
Servers MUST enforce the Access Control Lists (ACLs) set on address
books to ensure only authorised data is shared.
7. IANA Considerations
7.1. JMAP Capability Registration for "contacts"
IANA has registered "contacts" in the "JMAP Capabilities" registry as
follows:
Capability Name: urn:ietf:params:jmap:contacts
Intended Use: common
Change Controller: IETF
Security and Privacy Considerations: this document, Section 6
Reference: this document
7.2. JMAP Data Type Registration for "AddressBook"
IANA has registered "AddressBook" in the "JMAP Data Types" registry
as follows:
Type Name: AddressBook
Can Reference Blobs: No
Can Use for State Change: Yes
Capability: urn:ietf:params:jmap:contacts
Reference: this document
7.3. JMAP Data Type Registration for "ContactCard"
IANA has registered "ContactCard" in the "JMAP Data Types" registry
as follows:
Type Name: ContactCard
Can Reference Blobs: Yes
Can Use for State Change: Yes
Capability: urn:ietf:params:jmap:contacts
Reference: this document
7.4. JMAP Error Codes Registry
The following subsection has registered a new error code in the "JMAP
Error Codes" registry, as defined in Section 9 of [RFC8620].
7.4.1. addressBookHasContents
JMAP Error Code: addressBookHasContents
Intended Use: common
Change Controller: IETF
Description: The AddressBook has at least one ContactCard assigned
to it, and the "onDestroyRemoveContents" argument was false.
Reference: This document, Section 2.3
7.5. JSContact Property Registrations
IANA has registered the following additional properties in the
"JSContact Properties" registry, as defined in Section 3 of
[RFC9553].
7.5.1. id
Property Name: id
Property Type: not applicable
Property Context: Card
Intended Usage: reserved
Since Version: 1.0
Change Controller: IETF
Reference: this document
7.5.2. addressBookIds
Property Name: addressBookIds
Property Type: not applicable
Property Context: Card
Intended Usage: reserved
Since Version: 1.0
Change Controller: IETF
Reference: this document
7.5.3. blobId
Property Name: blobId
Property Type: not applicable
Property Context: Media
Intended Usage: reserved
Since Version: 1.0
Change Controller: IETF
Reference: this document
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397,
DOI 10.17487/RFC2397, August 1998,
<https://www.rfc-editor.org/info/rfc2397>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application
Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
2019, <https://www.rfc-editor.org/info/rfc8620>.
[RFC9553] Stepanek, R. and M. Loffredo, "JSContact: A JSON
Representation of Contact Data", RFC 9553,
DOI 10.17487/RFC9553, May 2024,
<https://www.rfc-editor.org/info/rfc9553>.
[RFC9670] Jenkins, N., Ed., "JSON Meta Application Protocol (JMAP)
Sharing", RFC 9670, DOI 10.17487/RFC9670, November 2024,
<https://www.rfc-editor.org/info/rfc9670>.
8.2. Informative References
[RFC8264] Saint-Andre, P. and M. Blanchet, "PRECIS Framework:
Preparation, Enforcement, and Comparison of
Internationalized Strings in Application Protocols",
RFC 8264, DOI 10.17487/RFC8264, October 2017,
<https://www.rfc-editor.org/info/rfc8264>.
[UNICODE] The Unicode Consortium, "The Unicode Standard",
<https://www.unicode.org/versions/latest/>.
Author's Address
Neil Jenkins (editor)
Fastmail
PO Box 234, Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com