JMAP J.M. Baum, Ed. Internet-Draft H.J. Happel, Ed. Intended status: Standards Track audriga Expires: 23 October 2021 21 April 2021 JMAP for Tasks draft-ietf-jmap-tasks-00 Abstract This document specifies a data model for synchronizing task data with a server using JMAP. 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 23 October 2021. Copyright Notice Copyright (c) 2021 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 Baum & Happel Expires 23 October 2021 [Page 1] Internet-Draft JMAP Tasks April 2021 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Data Model Overview . . . . . . . . . . . . . . . . . . . 4 1.4. Addition to the Capabilities Object . . . . . . . . . . . 4 1.4.1. urn:ietf:params:jmap:tasks . . . . . . . . . . . . . 4 2. Principals . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Principal Capability urn:ietf:params:jmap:tasks . . . . . 5 3. Assignee Identities . . . . . . . . . . . . . . . . . . . . . 5 3.1. AssigneeIdentity/get . . . . . . . . . . . . . . . . . . 6 3.2. AssigneeIdentity/changes . . . . . . . . . . . . . . . . 6 3.3. AssigneeIdentity/set . . . . . . . . . . . . . . . . . . 6 4. TaskLists . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. TaskList/get . . . . . . . . . . . . . . . . . . . . . . 8 4.2. TaskList/changes . . . . . . . . . . . . . . . . . . . . 9 4.3. TaskList/set . . . . . . . . . . . . . . . . . . . . . . 9 5. Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Additional JSCalendar properties . . . . . . . . . . . . 10 5.1.1. mayInviteSelf . . . . . . . . . . . . . . . . . . . . 10 5.1.2. mayInviteOthers . . . . . . . . . . . . . . . . . . . 10 5.1.3. hideAttendees . . . . . . . . . . . . . . . . . . . . 11 5.1.4. relatedTo . . . . . . . . . . . . . . . . . . . . . . 11 5.2. Properties similar in JMAP for Calendar . . . . . . . . . 11 5.3. Task/get . . . . . . . . . . . . . . . . . . . . . . . . 11 5.4. Task/changes . . . . . . . . . . . . . . . . . . . . . . 11 5.5. Task/set . . . . . . . . . . . . . . . . . . . . . . . . 11 5.6. Task/copy . . . . . . . . . . . . . . . . . . . . . . . . 12 5.7. Task/query . . . . . . . . . . . . . . . . . . . . . . . 12 5.8. Task/queryChanges . . . . . . . . . . . . . . . . . . . . 12 6. Task Notifications . . . . . . . . . . . . . . . . . . . . . 12 6.1. Object Properties . . . . . . . . . . . . . . . . . . . . 12 6.2. TaskNotification/get . . . . . . . . . . . . . . . . . . 13 6.3. TaskNotification/changes . . . . . . . . . . . . . . . . 13 6.4. TaskNotification/set . . . . . . . . . . . . . . . . . . 13 6.5. TaskNotification/query . . . . . . . . . . . . . . . . . 14 6.5.1. Filtering . . . . . . . . . . . . . . . . . . . . . . 14 6.5.2. Sorting . . . . . . . . . . . . . . . . . . . . . . . 14 6.6. TaskNotification/queryChanges . . . . . . . . . . . . . . 14 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 8.1. JMAP Capability Registration for "tasks" . . . . . . . . 14 8.2. JSCalendar Property Registrations . . . . . . . . . . . . 15 9. Normative References . . . . . . . . . . . . . . . . . . . . 15 10. Informative References . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 Baum & Happel Expires 23 October 2021 [Page 2] Internet-Draft JMAP Tasks April 2021 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. JMAP for Calendars ([I-D.ietf-jmap-calendars]) defines a data model for synchronizing calendar data between a client and a server using JMAP. The data model is designed to allow a server to provide consistent access to the same data via CalDAV [RFC4791] as well as JMAP. While CalDAV defines access to tasks, JMAP for Calendars does not. This specification fills this gap and defines a data model for synchronizing task data between a client and a server using JMAP. It is built upon JMAP for Calendars and reuses most of its definitions. For better readability this document only outlines differences between this specification and JMAP for Calendars. If not stated otherwise, the same specifics that apply to Calendar, CalendarEvent and CalendarEventNotification objects as defined in the aforemetioned specification also apply to similar data types introduced in this specification. 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]. Data types defined in the core specification are also used in this document. 1.2. Terminology The same terminology is used in this document as in the core JMAP specification, see [RFC8620], Section 1.6. The terms ParticipantIdentity, TaskList, Task and TaskNotification are used to refer to the data types defined in this document and instances of those data types. Baum & Happel Expires 23 October 2021 [Page 3] Internet-Draft JMAP Tasks April 2021 1.3. Data Model Overview Similar to JMAP for Calendar, an Account (see [RFC8620], Section 1.6.2) contains zero or more TaskList objects, which is a named collection of Tasks belonging to a Principal (see [I-D.jenkins-jmap-sharing] Section XXX). Task lists can also provide defaults, such as alerts and a color to apply to tasks in the calendar. Clients commonly let users toggle visibility of tasks belonging to a particular task list on/off. Servers may allow a task to belong to multiple TaskLists within an account. A Task is a representation of a single task or recurring series of Tasks in JSTask [I-D.ietf-calext-jscalendar] format. Recurrence rules and alerts as defined in JMAP for Calendars (see [I-D.ietf-jmap-calendars] Section XXX) apply. Just like the CalendarEventNotification objects (see [I-D.ietf-jmap-calendars] Section XXX), TaskNotification objects keep track of the history of changes made to a task by other users. Similarly, the ShareNotification type (see [I-D.jenkins-jmap-sharing] Section XXX) notifies the user when their access to another user's calendar is granted or revoked. 1.4. 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. 1.4.1. urn:ietf:params:jmap:tasks This represents support for the TaskList, Task and TaskNotification 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: * *shareesActAs*: "String" This MUST be one of: - "self" - sharees act as themselves when using tasks in this account. - "secretary"- sharees act as the principal to which this account belongs. Baum & Happel Expires 23 October 2021 [Page 4] Internet-Draft JMAP Tasks April 2021 * *minDateTime*: "LocalDate" The earliest date-time the server is willing to accept for any date stored in a Task. * *maxDateTime*: "LocalDate" The latest date-time the server is willing to accept for any date stored in a Task. * *maxExpandedQueryDuration*: "Duration" The maximum duration the user may query over when asking the server to expand recurrences. * *maxAssigneesPerTask*: "Number|null" The maximum number of assignees a single task may have, or null for no limit. * *mayCreateTaskList*: "Boolean" If true, the user may create a task list in this account. 2. Principals For systems that also support JMAP Sharing [RFC XXX], the tasks capability is used to indicate that this principal may be used with tasks. 2.1. Principal Capability urn:ietf:params:jmap:tasks A "urn:ietf:params:jmap:tasks" property is added to the Principal "capabilities" object, the value of which is an object with the following properties: * *accountId*: "Id|null" Id of Account with the "urn:ietf:params:jmap:tasks" capability that contains the task data for this principal, or null if none (e.g. the Principal is a group just used for permissions management), or the user does not have access to any data in the account. * *account*: "Account|null" The JMAP Account object corresponding to the accountId, null if none. * *sendTo*: "String[String]|null" If this principal may be added as a participant to an event, this is the map of methods for adding it, in the same format as Participant#sendTo in JSTask (see [I-D.ietf-calext-jscalendar], Section 4.4.5). 3. Assignee Identities An AssigneeIdentity stores information about a URI that represents the user within that account in an event's assignees. It has the following properties: * *id*: "Id" (immutable; server-set) The id of the AssigneeIdentity. Baum & Happel Expires 23 October 2021 [Page 5] Internet-Draft JMAP Tasks April 2021 * *name*: "String" (default: "") The display name of the assignee to use when adding this assignee to a task, e.g. "Jane Bloggs". * *sendTo*: "String[String]" Represents methods by which the participant may receive invitations and updates to an event. The keys in the property value are the available methods and MUST only contain ASCII alphanumeric characters (A-Za-z0-9). The value is a URI for the method specified in the key. An assignee in an task corresponds to an AssigneeIdentity if any of the method/uri pairs in the sendTo property of the participant are identical to a method/uri pair in the sendTo property of the identity. The following JMAP methods are supported. 3.1. AssigneeIdentity/get This is a standard "/get" method as described in [RFC8620], Section 5.1. The _ids_ argument may be "null" to fetch all at once. 3.2. AssigneeIdentity/changes This is a standard "/changes" method as described in [RFC8620], Section 5.2. 3.3. AssigneeIdentity/set This is a standard "/set" method as described in [RFC8620], Section 5.3. The server MAY restrict the uri values the user may claim, for example only allowing "mailto:" URIs with email addresses that belong to the user. A standard "forbidden" error is returned to reject non-permissible changes. 4. TaskLists A TaskList is a named collection of tasks. All tasks are associated with exactly one TaskList. A *TaskList* object has the following properties: * *id*: "Id" (immutable; server-set) The id of the task list. * *role*: "String|null" (default: null) Denotes the task list has a special purpose. This MUST be one of the following: - "inbox": This is the principal's default task list; Baum & Happel Expires 23 October 2021 [Page 6] Internet-Draft JMAP Tasks April 2021 - "trash": This task list holds messages the user has discarded; * *name*: "String" The user-visible name of the task list. This may be any UTF-8 string of at least 1 character in length and maximum 255 octets in size. * *description*: "String|null" (default: null) An optional longer- form description of the task list, to provide context in shared environments where users need more than just the name. * *color*: "String|null" (default: null) A color to be used when displaying events associated with the task list. If not null, the value MUST be a case-insensitive color name taken from the set of names defined in Section 4.3 of CSS Color Module Level 3 COLORS (https://www.w3.org/TR/css-color-3/), or an RGB value in hexadecimal notation, as defined in Section 4.2.1 of CSS Color Module Level 3. The color SHOULD have sufficient contrast to be used as text on a white background. * *sortOrder*: "UnsignedInt" (default: 0) Defines the sort order of task lists 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.) A task list with a lower order should be displayed before a list with a higher order in any list of task lists in the client's UI. Task lists with equal order SHOULD be sorted in alphabetical order by name. The sorting should take into account locale-specific character order convention. * *isSubscribed*: "Boolean" Has the user indicated they wish to see this task list in their client? This SHOULD default to false for task lists in shared accounts the user has access to and true for any new task list created by the user themself. If false, the task list should only be displayed when the user explicitly requests it or to offer it for the user to subscribe to. * *defaultAlertsWithTime*: "Id[Alert]|null" (default: null) A map of alert ids to Alert objects (see [I-D.ietf-calext-jscalendar], Section 4.5.2) to apply for events where "showWithoutTime" is false and "useDefaultAlerts" is true. Ids MUST be unique across all default alerts in the account, including those in other task lists; a UUID is recommended. Baum & Happel Expires 23 October 2021 [Page 7] Internet-Draft JMAP Tasks April 2021 * *defaultAlertsWithoutTime*: "Id[Alert]|null" (default: null) A map of alert ids to Alert objects (see [I-D.ietf-calext-jscalendar], Section 4.5.2) to apply for events where "showWithoutTime" is true and "useDefaultAlerts" is true. Ids MUST be unique across all default alerts in the account, including those in other task lists; a UUID is recommended. * *timeZone*: "String|null" (default: null) The time zone to use for events without a time zone when the server needs to resolve them into absolute time, e.g., for alerts or availability calculation. The value MUST be a time zone id from the IANA Time Zone Database TZDB (https://www.iana.org/time-zones). If "null", the timeZone of the account's associated Principal will be used. Clients SHOULD use this as the default for new events in this task list if set. * *shareWith*: "Id[CalendarRights]|null" (default: null) A map of Principal id to rights for principals this calendar is shared with. The principal to which this task list belongs MUST NOT be in this set. This is null if the user requesting the object does not have the mayAdmin right, or if the task list is not shared with anyone. May be modified only if the user has the mayAdmin 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 calendar belongs. The user is an *owner* for a task if the Task object has an "assignee" property, and one of the Participant objects both: 1. Has the "chair" role. 2. Corresponds to one of the user's AssigneeIdentity objects in the account. A task has no owner if its assignee property is null or omitted. TODO currently disregarding "myRights" 4.1. TaskList/get This is a standard "/get" method as described in [RFC8620], Section 5.1. The _ids_ argument may be "null" to fetch all at once. TODO add part about rights properties. Baum & Happel Expires 23 October 2021 [Page 8] Internet-Draft JMAP Tasks April 2021 4.2. TaskList/changes This is a standard "/changes" method as described in [RFC8620], Section 5.2. 4.3. TaskList/set This is the "Calendar/set" method as described in [I-D.ietf-jmap-calendars], Section XXX. TODO copy+paste from "Calendar/set" and replace "onDestroyRemoveEvents" by "onDestroyRemoveTasks" (and "calendarHasEvent"). 5. Tasks A *Task* object contains information about a task, or recurring series of tasks. It is a JSTask object, as defined in [I-D.ietf-calext-jscalendar], with the following additional properties: * *id*: "Id" The id of the Task. This property is immutable. The id uniquely identifies a JSTask with a particular "uid" and "recurrenceId" within a particular account. * *taskListId*: "Id" The TaskList id this task belongs to. A task MUST belong to exactly one TaskList at all times (until it is destroyed). * *isDraft*: "Boolean" If true, this task is to be considered a draft. The server will not send any push notifications for alerts. This may only be set to true upon creation. Once set to false, the value cannot be updated to true. This property MUST NOT appear in "recurrenceOverrides". * *utcStart*: "UTCDate" For simple clients that do not or cannot implement time zone support. Clients should only use this if also asking the server to expand recurrences, as you cannot accurately expand a recurrence without the original time zone. This property is calculated at fetch time by the server. Time zones are political, and they can and do change at any time. Fetching exactly the same property again may return different results if the time zone data has been updated on the server. Time zone data changes are not considered "updates" to the task. If set, the server will convert to the task's current time zone using its current time zone data and store the local time. Baum & Happel Expires 23 October 2021 [Page 9] Internet-Draft JMAP Tasks April 2021 This is not included by default and must be requested explicitly. Floating tasks (tasks without a time zone) will be interpreted as per the time zone given as a Task/get argument. Note that it is not possible to accurately calculate the expansion of recurrence rules or recurrence overrides with the utcStart property rather than the local start time. Even simple recurrences such as "repeat weekly" may cross a daylight-savings boundary and end up at a different UTC time. Clients that wish to use "utcStart" are RECOMMENDED to request the server expand recurrences (see Section XXX). * *utcDue*: "UTCDate" The server calculates the end time in UTC from the start/timeZone/duration properties of the task. This is not included by default and must be requested explicitly. Like utcStart, this is calculated at fetch time if requested and may change due to time zone data changes. Floating tasks will be interpreted as per the time zone given as a Task/get argument. * *sortOrder*: "UnsignedInt" (default: 0) Defines the sort order of a task 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.) A task with a lower order should be displayed before a task with a higher order in any list of tasks in the client's UI. Tasks with equal order SHOULD be sorted in alphabetical order by name. The sorting should take into account locale-specific character order convention. 5.1. Additional JSCalendar properties This document defines four new JSCalendar properties. 5.1.1. mayInviteSelf Type: "Boolean" (default: false) If "true", any user that has access to the event may add themselves to it as a participant with the "attendee" role. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the master object. 5.1.2. mayInviteOthers Type: "Boolean" (default: false) Baum & Happel Expires 23 October 2021 [Page 10] Internet-Draft JMAP Tasks April 2021 If "true", any current participant with the "attendee" role may add new participants with the "attendee" role to the event. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the master object. 5.1.3. hideAttendees Type: "Boolean" (default: false) If "true", only the owners of the event may see the full set of participants. Other sharees of the event may only see the owners and themselves. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the master object. 5.1.4. relatedTo Type: "Id[String]|null" (default: null) A map of task ids to relations. Relation SHOULD be one of: - "blockedBy": Blocked by task with id. - "clonedBy": Task with id was cloned from this issue. - "duplicatedBy": Task with id is a duplicate of this issue. - "causedBy": Task with id was the cause for this task. - "relatesTo": Task with id is related. - "childOf": Task with id is parent. 5.2. Properties similar in JMAP for Calendar Attachments, per-user properties, recurrences and updates to recurrences are described in [I-D.ietf-jmap-calendars], Section XXX. 5.3. Task/get This is the "CalendarEvent/get" method as described in [I-D.ietf-jmap-calendars], Section XXX. TODO redefine this here. Similar to "TaskList/get" we only need to replace a few definitions. For example, replace "reduceParticipants" with "reduceAssignees". Copy+Paste most of the stuff. 5.4. Task/changes This is a standard "/changes" method as described in [RFC8620], Section 5.2. 5.5. Task/set This is the "CalendarEvent/set" method as described in [I-D.ietf-jmap-calendars], Section XXX. Baum & Happel Expires 23 October 2021 [Page 11] Internet-Draft JMAP Tasks April 2021 TODO copy+paste most stuff from "CalendarEvent/set". It should be fine to just reference patching. 5.6. Task/copy This is a standard "/copy" method as described in [RFC8620], Section 5.4. 5.7. Task/query This is the "CalendarEvent/query" method as described in [I-D.ietf-jmap-calendars], Section XXX. TODO copy+paste most stuff from "CalendarEvent/query". Mainly filtering should be different. 5.8. Task/queryChanges This is a standard "/queryChanges" method as described in [RFC8620], Section 5.6. 6. Task Notifications The TaskNotification data type records changes made by external entities to tasks in calendars the user is subscribed to. Notifications are stored in the same Account as the Task that was changed. This is the same specification as the CalendarEventNotification object from [I-D.ietf-jmap-calendars], Section XXX. Only the object properties differ slightly and are therefore fully described in this document. 6.1. Object Properties The *TaskNotification* object has the following properties: * *id*: "String" The id of the TaskNotification. * *created*: "UTCDate" The time this notification was created. * *changedBy*: "Person" Who made the change. - *name*: "String" The name of the person who made the change. - *email*: "String" The email of the person who made the change, or null if no email is available. Baum & Happel Expires 23 October 2021 [Page 12] Internet-Draft JMAP Tasks April 2021 - *principalId*: "String|null" The id of the principal corresponding to the person who made the change, if any. This will be null if the change was due to receving an iTIP message. * *comment*: "String|null" Comment sent along with the change by the user that made it. (e.g. COMMENT property in an iTIP message). * *type*: "String" This MUST be one of - created - updated - destroyed * *TaskId*: "String" The id of the Task that this notification is about. * *isDraft*: "Boolean" (created/updated only) Is this event a draft? * *event*: "JSTask" The data before the change (if updated or destroyed), or the data after creation (if created). * *eventPatch*: "PatchObject" (updated only) A patch encoding the change between the data in the event property, and the data after the update. To reduce data, if the change only affects a single instance of a recurring event, the server MAY set the event and eventPatch properties for the instance; the calendarEventId MUST still be for the master event. 6.2. TaskNotification/get This is a standard "/get" method as described in [RFC8620], Section 5.1. 6.3. TaskNotification/changes This is a standard "/changes" method as described in [RFC8620], Section 5.2. 6.4. TaskNotification/set This is a standard "/changes" method as described in [RFC8620], Section 5.3. Baum & Happel Expires 23 October 2021 [Page 13] Internet-Draft JMAP Tasks April 2021 Only destroy is supported; any attempt to create/update MUST be rejected with a "forbidden" SetError. 6.5. TaskNotification/query This is a standard "/query" method as described in [RFC8620], Section 5.5. 6.5.1. Filtering A *FilterCondition* object has the following properties: * *after*: "UTCDate|null" The creation date must be on or after this date to match the condition. * *before*: "UTCDate|null" The creation date must be before this date to match the condition. * *type*: "String" The type property must be the same to match the condition. * *taskIds*: "Id[]|null" A list of task ids. The taskId property of the notification must be in this list to match the condition. 6.5.2. Sorting The "created" property MUST be supported for sorting. 6.6. TaskNotification/queryChanges This is a standard "/queryChanges" method as described in [RFC8620], Section 5.6. 7. Security Considerations All security considerations of JMAP for Calendars [I-D.ietf-jmap-calendars] apply to this specification. 8. IANA Considerations 8.1. JMAP Capability Registration for "tasks" TODO Actually register IANA will register the "tasks" JMAP Capability as follows: Capability Name: "urn:ietf:params:jmap:tasks" Baum & Happel Expires 23 October 2021 [Page 14] Internet-Draft JMAP Tasks April 2021 Specification document: this document Intended use: common Change Controller: IETF Security and privacy considerations: this document, Section XXX 8.2. JSCalendar Property Registrations All IANA registrations for JSTask are described in JMAP for Calendars [I-D.ietf-jmap-calendars]. 9. Normative References [I-D.ietf-calext-jscalendar] Jenkins, N. and R. Stepanek, "JSCalendar: A JSON representation of calendar data", Work in Progress, Internet-Draft, draft-ietf-calext-jscalendar-32, 15 October 2020, . [I-D.ietf-jmap-calendars] Jenkins, N. and M. Douglass, "JMAP for Calendars", Work in Progress, Internet-Draft, draft-ietf-jmap-calendars-05, 24 January 2021, . [I-D.jenkins-jmap-sharing] Jenkins, N., "JMAP Sharing", Work in Progress, Internet- Draft, draft-jenkins-jmap-sharing-00, 15 December 2020, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July 2019, . 10. Informative References Baum & Happel Expires 23 October 2021 [Page 15] Internet-Draft JMAP Tasks April 2021 [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, DOI 10.17487/RFC4791, March 2007, . Authors' Addresses Joris Baum (editor) audriga Durlacher Allee 47 76131 Karlsruhe Germany Email: joris@audriga.com URI: https://www.audriga.com Hans-Joerg (editor) audriga Durlacher Allee 47 76131 Karlsruhe Germany Email: hans-joerg@audriga.com URI: https://www.audriga.com Baum & Happel Expires 23 October 2021 [Page 16]