Internet-Draft JMAP Sieve February 2024
Murchison Expires 9 August 2024 [Page]
Workgroup:
JMAP
Internet-Draft:
draft-ietf-jmap-sieve-18
Published:
Intended Status:
Standards Track
Expires:
Author:
K. Murchison
Fastmail

JMAP for Sieve Scripts

Abstract

This document specifies a data model for managing Sieve scripts on a server using the JSON Meta Application Protocol (JMAP). Clients can use this protocol to efficiently search, access, organize, and validate Sieve scripts.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 9 August 2024.

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Table of Contents

1. Introduction

JMAP [RFC8620] (JSON Meta Application Protocol) is a generic protocol for synchronizing data, such as mail, calendars or contacts, between a client and a server. It is optimized for mobile and web environments, and aims to provide a consistent interface to different data types.

This specification defines a data model for managing Sieve [RFC5228] scripts on a server using JMAP. The data model is designed to allow a server to provide consistent access to the same scripts via ManageSieve [RFC5804] as well as 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]. This document also uses data types and terminology established in Sections 1.2-1.6 of [RFC8620].

The term SieveScript (with this specific capitalization) is used to refer to the data type defined in this document and instances of those data types. Servers MUST support all properties specified for the data type defined in this document.

1.2. Addition to the Capabilities Object

The capabilities object is returned as part of the JMAP Session object; see [RFC8620], Section 2. This document defines one additional capability URI.

1.2.1. urn:ietf:params:jmap:sieve

The urn:ietf:params:jmap:sieve URI represents support for the SieveScript data type and associated API methods. The value of this property in the JMAP Session capabilities property is an object that MUST contain the following information on server capabilities:

  • implementation: String

    The name and version of the Sieve implementation.

The value of this property in an account's accountCapabilities property is an object that MUST contain the following information on per-account server capabilities:

  • maxSizeScriptName: UnsignedInt

    The maximum length, in (UTF-8) octets, allowed for the name of a SieveScript. For compatibility with ManageSieve, this MUST be at least 512 (up to 128 Unicode characters).

  • maxSizeScript: UnsignedInt|null

    The maximum size (in octets) of a Sieve script the server is willing to store for the user, or null for no limit.

  • maxNumberScripts: UnsignedInt|null

    The maximum number of Sieve scripts the server is willing to store for the user, or null for no limit.

  • maxNumberRedirects: UnsignedInt|null

    The maximum number of Sieve "redirect" actions a script can perform during a single evaluation or null for no limit. Note that this is different from the total number of "redirect" actions a script can contain.

  • sieveExtensions: String[]

    A list of case-sensitive Sieve capability strings (as listed in Sieve "require" action; see [RFC5228], Section 3.2) indicating the extensions supported by the Sieve engine.

  • notificationMethods: String[]|null

    A list of URI schema parts [RFC3986] for notification methods supported by the Sieve "enotify" [RFC5435] extension, or null if the extension is not supported by the Sieve engine.

  • externalLists: String[]|null

    A list of URI schema parts [RFC3986] for externally stored list types supported by the Sieve "extlists" [RFC6134] extension, or null if the extension is not supported by the Sieve engine.

1.2.2. Example

A JMAP Session object showing a user that has access to their own Sieve scripts with support for a few Sieve extensions:

{
  "capabilities": {
    "urn:ietf:params:jmap:core": {
      ...
    },
    "urn:ietf:params:jmap:mail": {},
    "urn:ietf:params:jmap:quota": {},
    "urn:ietf:params:jmap:blob": {},
    "urn:ietf:params:jmap:sieve": {
      "implementation": "ACME Email Filtering"
    },
    "urn:ietf:params:jmap:vacationresponse": {},
    ...
  },
  "accounts": {
    "ken": {
      "name": "ken@example.com",
      "isPersonal": true,
      "isReadOnly": false,
      "accountCapabilities": {
        "urn:ietf:params:jmap:core": {},
        "urn:ietf:params:jmap:quota": {},
        "urn:ietf:params:jmap:mail": {
          ...
        },
        "urn:ietf:params:jmap:blob": {
          "supportedTypeNames": [
            "Email"
            "SieveScript",
            ...
          ],
          ...
        },
        "urn:ietf:params:jmap:sieve": {
          "maxSizeScriptName": 512,
          "maxSizeScript": 65536,
          "maxNumberScripts": 5,
          "maxNumberRedirects": null,
          "sieveExtensions": [
            "fileinto",
            "imap4flags",
            "enotify",
            ...
          ],
          "notificationMethods": [
            "mailto"
          ],
          "externalLists": null,
        },
        "urn:ietf:params:jmap:vacationresponse": {},
        ...
      },
      ...
    }
  },
  "primaryAccounts": {
    "urn:ietf:params:jmap:mail": "ken",
    "urn:ietf:params:jmap:sieve": "ken",
    "urn:ietf:params:jmap:vacationresponse": "ken",
    ...
  },
  "username": "ken@example.com",
  "apiUrl": "/jmap/",
  "downloadUrl":
    "/jmap/download/{accountId}/{blobId}/{name}?accept={type}",
  "uploadUrl": "/jmap/upload/{accountId}/",
  ...
}

2. Sieve Scripts

A SieveScript object represents a single Sieve [RFC5228] script for filtering email messages at time of final delivery.

2.1. Sieve Script Properties

A SieveScript object has the following properties:

  • id: Id (immutable; server-set)

    The id of the script.

  • name: String|null (optional; default is server-dependent)

    User-visible name for the SieveScript. If non-null, this MUST be a Net-Unicode [RFC5198] string of at least 1 character in length, subject to the maximum size given in the capability object. For compatibility with ManageSieve, servers MUST reject names that contain control characters. Servers MAY reject names that violate server policy (e.g., names containing slash (/)). The name MUST be unique among all SieveScripts within an account.

  • blobId: Id

    The id of the blob containing the raw octets of the script.

  • isActive: Boolean (server-set; default: false)

    Indicator that the SieveScript is actively filtering incoming messages. A user may have at most one active script. The SieveScript/set (Section 2.4) method is used for changing the active script or disabling Sieve processing.

2.2. Sieve Script Content

A script MUST be UTF-8 [RFC3629] content of at least 1 character in length, subject to the syntax of Sieve [RFC5228]. A script MUST NOT contain any "require" statement(s) mentioning Sieve capability strings not present in the capability (Section 1.2.1) object. Note that if the Sieve "ihave" [RFC5463] capability string is present in the capability object, the script MAY mention unrecognized/unsupported extensions in the "ihave" test.

Script content is treated as a binary blob and uploaded/downloaded via the mechanisms in [RFC8620] Sections 6.1/6.2 respectively and/or via the JMAP Blob management methods in [RFC9404] Sections 4.1/4.2 respectively.

Downloading script content via the JMAP downloadUrl or the Blob/get method provides equivalent functionality to the GETSCRIPT command in [RFC5804].

2.3. SieveScript/get

This is a standard "/get" method as described in [RFC8620], Section 5.1. The ids argument may be null to fetch all scripts at once.

This method provides equivalent functionality to the LISTSCRIPTS command in [RFC5804].

2.3.1. Examples

Request (and response) to list all scripts:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/get", {
      "accountId": "ken"
    }, "0"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/get",
      {
        "state": "1634915373.240633104-120",
        "list": [
          {
            "id": "2d647053-dded-418d-917a-63eda3ac8f7b",
            "name": "test1",
            "isActive": true,
            "blobId": "S7"
          }
        ],
        "notFound": [],
        "accountId": "ken"
      },
      "0"
    ]
  ]
}

Request (and response) to download the script content via the JMAP downloadUrl as advertised in Section 1.2.2:

GET /jmap/download/ken/S7/test1.siv?accept=application/sieve HTTP/1.1
Host: jmap.example.com
Authorization: Basic a2VuOnBhc3N3b3Jk

HTTP/1.1 200 OK
Date: Fri, 22 Oct 2021 15:27:38 GMT
Content-Type: application/sieve; charset=utf-8
Content-Disposition: attachment; filename="test1.siv"
Content-Length: 49

require ["fileinto"];
fileinto "INBOX.target";

Request (and response) to fetch script properties and content in a single JMAP API request using the JMAP Blob management extension [RFC9404]:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:blob",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/get", {
      "accountId": "ken",
      "ids": [ "2d647053-dded-418d-917a-63eda3ac8f7b" ]
    }, "0"],
    ["Blob/get", {
      "accountId": "ken",
      "#ids": {
        "resultOf": "0",
        "name": "SieveScript/get",
        "path": "/list/*/blobId"
      }
    }, "1"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/get",
      {
        "state": "1634915373.240633104-120",
        "list": [
          {
            "id": "2d647053-dded-418d-917a-63eda3ac8f7b",
            "name": "test1",
            "isActive": true,
            "blobId": "S7"
          }
        ],
        "notFound": [],
        "accountId": "ken"
      },
      "0"
    ],
    [
      "Blob/get",
      {
        "list": [
          {
            "id": "S7",
            "data:asText":
 "require [\"fileinto\"];\\r\\nfileinto \"INBOX.target\";\\r\\n",
            "size": 49
          }
        ],
        "notFound": [],
        "accountId": "ken"
      },
      "1"
    ]
  ]
}

2.4. SieveScript/set

This is a standard "/set" method as described in [RFC8620], Section 5.3 but with the following additional request arguments, either or both of which may be omitted:

  • onSuccessActivateScript: Id (optional)

    The id of the SieveScript to activate if and only if all of the creations, modifications, and destructions (if any) succeed. (For references to SieveScript creations, this is equivalent to a creation-reference, so the id will be the creation id prefixed with a "#".) The currently active SieveScript (if any) will be deactivated before activating the specified SieveScript.

    If the id is either illegal or nonexistent, it MUST be ignored and the currently active SieveScript (if any) will remain as such.

    The id of any activated SieveScript MUST be reported in either the "created" or "updated" argument in the response as appropriate, including a value of "true" for the "isActive" property. The id of any deactivated SieveScript MUST be reported in the "updated" argument in the response, including a value of "false" for the "isActive" property.

  • onSuccessDeactivateScript: Boolean (optional)

    If true, the currently active SieveScript (if any) will be deactivated if and only if all of the creations, modifications, and destructions (if any) succeed. If false, the currently active SieveScript (if any) will remain as such.

    The id of any deactivated SieveScript MUST be reported in the "updated" argument in the response, including a value of "false" for the "isActive" property.

If both the onSuccessActivateScript and onSuccessDeactivateScript arguments are present in the request, then onSuccessDeactivateScript MUST be processed first. If neither argument is present in the request, the currently active SieveScript (if any) will remain as such.

This method provides equivalent functionality to the PUTSCRIPT, DELETESCRIPT, RENAMESCRIPT, and SETACTIVE commands in [RFC5804].

Script content must first be uploaded as per Section 2.2 prior to referencing it in a SieveScript/set call.

If the SieveScript can not be created or updated because it would result in two SieveScripts with the same name, the server MUST reject the request with an "alreadyExists" SetError. An "existingId" property of type "Id" MUST be included on the SetError object with the id of the existing SieveScript.

If the SieveScript can not be created or updated because its size exceeds the "maxSizeScript" limit, the server MUST reject the request with a "tooLarge" SetError.

If the SieveScript can not be created because it would exceed the "maxNumberScripts" limit or would exceed a server-imposed storage limit, the server MUST reject the request with an "overQuota" SetError.

The active SieveScript MUST NOT be destroyed unless it is first deactivated in a separate SieveScript/set method call.

The following extra SetError types are defined:

For "create" and "update":

  • invalidSieve:

    The SieveScript content violates the Sieve [RFC5228] grammar and/or one or more extensions mentioned in the script's "require" statement(s) are not supported by the Sieve interpreter. The description property on the SetError object SHOULD contain a specific error message giving at least the line number of the first error.

For "destroy":

  • sieveIsActive:

    The SieveScript is active.

2.4.1. Examples

Request (and response) to upload a script requiring the Imap4Flags [RFC5232] Extension using the JMAP uploadUrl as advertised in Section 1.2.2:

POST /jmap/upload/ken/ HTTP/1.1
Host: jmap.example.com
Authorization: Basic a2VuOnBhc3N3b3Jk
Content-Type: application/sieve
Content-Length: 98

require "imapflags";

if address :is ["To", "Cc"] "jmap@ietf.org" {
  setflag "\\Flagged";
}


HTTP/1.1 201 Created
Date: Thu, 10 Dec 2020 17:14:31 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 171

{
  "accountId": "ken",
  "blobId": "Gabcc83e44a6e19991c4568d0b94e1767c83dd123",
  "type": "application/sieve"
  "size": 98
}

Request (and response) to create and activate a script using the uploaded blob. Note that the response shows that an existing active script has been deactivated in lieu of the newly created script being activated.

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/set", {
      "accountId": "ken",
      "create": {
        "A": {
          "name": null,
          "blobId": "Gabcc83e44a6e19991c4568d0b94e1767c83dd123"
        }
      },
      "onSuccessActivateScript": "#A"
    }, "0"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/set",
      {
        "oldState": "1603741717.50737918-4096",
        "newState": "1603741751.227268529-4096",
        "created": {
          "A": {
            "id": "dd1b164f-8cdc-448c-9f54",
            "name": "ken-20201210T171432-0",
            "blobId": "Sdd1b164f-8cdc-448c-9f54",
            "isActive": true
          }
        },
        "updated": {
          "8abd6f4a-bcb4d-87650-3fcd": {
            "isActive": false
          }
        },
        "destroyed": null,
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "0"
    ]
  ]
}

Request (and response) to update script content using the JMAP Blob management extension [RFC9404]:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:blob",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["Blob/upload", {
      "accountId": "ken",
      "create": {
        "B": {
          "data": [ {
            "data:asText":
              "redirect \"ken@example.com\"\r\n;"
           } ],
          "type": "application/sieve"
        }
      }
    }, "1"],
    ["SieveScript/set", {
      "accountId": "ken",
      "update": { "dd1b164f-8cdc-448c-9f54": {
        "blobId": "#B"
        }
      }
    }, "2"]
  ]
}

{
  "methodResponses": [
    [
      "Blob/upload",
      {
        "oldState": null,
        "newState": "1603741700.309607123-0128",
        "created": {
          "B": {
            "id": "G969c83e44a6e10871c4568d0b94e1767c83ddeae",
            "blobId": "G969c83e44a6e10871c4568d0b94e1767c83ddeae",
            "type": "application/sieve",
            "size": 29
          }
        },
        "notCreated": null,
        "accountId": "ken"
      },
      "1"
    ],
    [
      "SieveScript/set",
      {
        "oldState": "1603741751.227268529-4096",
        "newState": "1603742603.309607868-4096",
        "created": null,
        "updated": {
          "dd1b164f-8cdc-448c-9f54": null
        },
        "destroyed": null,
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "2"
    ]
  ]
}

Request (and response) to update script name and deactivate:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/set", {
      "accountId": "ken",
      "update": { "dd1b164f-8cdc-448c-9f54": {
        "name": "myscript"
        }
      },
      "onSuccessDeactivateScript": true
    }, "3"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/set",
      {
        "oldState": "1603742603.309607868-4096",
        "newState": "1603742967.852315428-4096",
        "created": null,
        "updated": {
          "dd1b164f-8cdc-448c-9f54": {
            "isActive": false
          }
        },
        "destroyed": null,
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "3"
    ]
  ]
}

Request (and response) to activate a script:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/set", {
      "accountId": "ken",
      "onSuccessActivateScript": "dd1b164f-8cdc-448c-9f54"
    }, "4"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/set",
      {
        "oldState": "1603742967.852315428-4096",
        "newState": "1603744460.316617118-4096",
        "created": null,
        "updated": {
          "dd1b164f-8cdc-448c-9f54": {
            "isActive": true
          }
        },
        "destroyed": null,
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "4"
    ]
  ]
}

Requests (and responses) to deactivate and destroy the active script:

{
  "using": [ "urn:ietf:params:jmap:core",
             "urn:ietf:params:jmap:sieve" ],
  "methodCalls": [
    ["SieveScript/set", {
      "accountId": "ken",
      "onSuccessDeactivateScript": true
    }, "5"],
    ["SieveScript/set", {
      "accountId": "ken",
      "destroy": [ "dd1b164f-8cdc-448c-9f54" ]
    }, "6"]
  ]
}

{
  "methodResponses": [
    [
      "SieveScript/set",
      {
        "oldState": "1603744460.316617118-4096",
        "newState": "1603744637.575375572-4096",
        "created": null,
        "updated": {
          "dd1b164f-8cdc-448c-9f54": {
            "isActive": false
          }
        },
        "destroyed": null,
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "5"
    ],
    [
      "SieveScript/set",
      {
        "oldState": "1603744637.575375572-4096",
        "newState": "1603744637.854390875-4096",
        "created": null,
        "updated": null,
        "destroyed": [
          "dd1b164f-8cdc-448c-9f54"
        ],
        "notCreated": null,
        "notUpdated": null,
        "notDestroyed": null,
        "accountId": "ken"
      },
      "6"
    ]
  ]
}

2.5. SieveScript/query

This is a standard "/query" method as described in [RFC8620], Section 5.5. A FilterCondition object has the following properties, either of which may be omitted:

  • name: String

    The SieveScript "name" property contains the given string.

  • isActive: Boolean

    The "isActive" property of the SieveScript must be identical to the value given to match the condition.

The following SieveScript properties MUST be supported for sorting:

2.6. SieveScript/validate

This method is used by the client to verify Sieve script validity without storing the script on the server, providing equivalent functionality to the CHECKSCRIPT command in [RFC5804].

The method takes the following arguments:

  • accountId: Id

    The id of the account to use.

  • blobId: Id

    The id of the blob containing the raw octets of the script to validate, subject to the same requirements in Section 2.

The response has the following arguments:

  • accountId: Id

    The id of the account used for this call.

  • error: SetError|null

    An "invalidSieve" SetError object if the script content is invalid (see Section 2.4), or null if the script content is valid.

As with the SieveScript/set (Section 2.4) method, script content must first be uploaded as a blob using either the standard upload mechanism (see [RFC8620] Section 6.1) or the JMAP Blob management extension (see [RFC9404] Section 4.1).

3. Quotas

Servers SHOULD impose quotas on Sieve scripts to prevent malicious users from exceeding available storage. Administration of such quotas is outside of the scope of this specification, however [RFC9425] defines a data model for users to obtain quota details over JMAP.

The mechanism for handling SieveScript requests that would place a user over a quota setting is discussed in Section 2.4.

4. Compatibility with JMAP Vacation Response

Section 8 of [RFC8621] defines a VacationResponse object to represent an autoresponder to incoming email messages. Servers that implement the VacationResponse as a Sieve script that resides amongst other user scripts are subject to the following requirements:

5. Security Considerations

All security considerations of JMAP [RFC8620] and Sieve [RFC5228] apply to this specification.

6. IANA Considerations

6.1. JMAP Capability Registration for "sieve"

IANA will register the "sieve" JMAP Capability as follows:

Capability Name: urn:ietf:params:jmap:sieve

Specification document: this document

Intended use: common

Change Controller: IETF

Security and privacy considerations: this document, Section 5

6.2. JMAP Data Type Registration for "SieveScript"

IANA will register the "SieveScript" JMAP Data Type as follows:

Type Name: SieveScript

Can Reference Blobs: yes

Can Use for State Change: yes

Capability: urn:ietf:params:jmap:sieve

Specification document: this document

6.3. JMAP Error Codes Registry

The following sub-sections register two new error codes in the JMAP Error Codes registry, as defined in [RFC8620].

6.3.1. invalidSieve

JMAP Error Code: invalidSieve

Intended use: common

Change controller: IETF

Reference: This document, Section 2.4

Description: The SieveScript violates the Sieve grammar [RFC5228] and/or one or more extensions mentioned in the script's "require" statement(s) are not supported by the Sieve interpreter.

6.3.2. sieveIsActive

JMAP Error Code: sieveIsActive

Intended use: common

Change controller: IETF

Reference: This document, Section 2.4

Description: The client tried to destroy the active SieveScript.

7. Acknowledgments

The concepts in this document are based largely on those in [RFC5804]. The author would like to thank the authors of that document for providing both inspiration and some borrowed text for this document.

The author would also like to thank the following individuals for contributing their ideas and support for writing this specification: Joris Baum, Mauro De Gennaro, Bron Gondwana, Neil Jenkins, Alexey Melnikov, and Ricardo Signes.

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, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3629]
Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, , <https://www.rfc-editor.org/info/rfc3629>.
[RFC3986]
Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, , <https://www.rfc-editor.org/info/rfc3986>.
[RFC5198]
Klensin, J. and M. Padlipsky, "Unicode Format for Network Interchange", RFC 5198, DOI 10.17487/RFC5198, , <https://www.rfc-editor.org/info/rfc5198>.
[RFC5228]
Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email Filtering Language", RFC 5228, DOI 10.17487/RFC5228, , <https://www.rfc-editor.org/info/rfc5228>.
[RFC5435]
Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T. Martin, "Sieve Email Filtering: Extension for Notifications", RFC 5435, DOI 10.17487/RFC5435, , <https://www.rfc-editor.org/info/rfc5435>.
[RFC6134]
Melnikov, A. and B. Leiba, "Sieve Extension: Externally Stored Lists", RFC 6134, DOI 10.17487/RFC6134, , <https://www.rfc-editor.org/info/rfc6134>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <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, , <https://www.rfc-editor.org/info/rfc8620>.
[RFC8621]
Jenkins, N. and C. Newman, "The JSON Meta Application Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621, , <https://www.rfc-editor.org/info/rfc8621>.

8.2. Informative References

[RFC5232]
Melnikov, A., "Sieve Email Filtering: Imap4flags Extension", RFC 5232, DOI 10.17487/RFC5232, , <https://www.rfc-editor.org/info/rfc5232>.
[RFC5463]
Freed, N., "Sieve Email Filtering: Ihave Extension", RFC 5463, DOI 10.17487/RFC5463, , <https://www.rfc-editor.org/info/rfc5463>.
[RFC5804]
Melnikov, A., Ed. and T. Martin, "A Protocol for Remotely Managing Sieve Scripts", RFC 5804, DOI 10.17487/RFC5804, , <https://www.rfc-editor.org/info/rfc5804>.
[RFC9404]
Gondwana, B., Ed., "JSON Meta Application Protocol (JMAP) Blob Management Extension", RFC 9404, DOI 10.17487/RFC9404, , <https://www.rfc-editor.org/info/rfc9404>.
[RFC9425]
Cordier, R., Ed., "JSON Meta Application Protocol (JMAP) for Quotas", RFC 9425, DOI 10.17487/RFC9425, , <https://www.rfc-editor.org/info/rfc9425>.

Appendix A. Change History (To be removed by RFC Editor before publication)

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Author's Address

Kenneth Murchison
Fastmail US LLC
1429 Walnut Street - Suite 1201
Philadelphia, PA 19102
United States of America