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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Apthorp 3 Internet-Draft DHL Express 4 Updates: 5545 (if approved) M. Douglass 5 Intended status: Standards Track Bedework Commercial Services 6 Expires: 22 September 2022 21 March 2022 8 Task Extensions to iCalendar 9 draft-ietf-calext-ical-tasks-03 11 Abstract 13 This document defines extensions to the Internet Calendaring and 14 Scheduling Core Object Specification (iCalendar) (RFC5545) to provide 15 improved status tracking, scheduling and specification of tasks. 17 It also defines how Calendaring Extensions to WebDAV (CalDAV) (RFC 18 4791) servers can be extended to support certain automated task 19 management behaviours. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on 22 September 2022. 38 Copyright Notice 40 Copyright (c) 2022 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 45 license-info) in effect on the date of publication of this document. 46 Please review these documents carefully, as they describe your rights 47 and restrictions with respect to this document. Code Components 48 extracted from this document must include Revised BSD License text as 49 described in Section 4.e of the Trust Legal Provisions and are 50 provided without warranty as described in the Revised BSD License. 52 Table of Contents 54 1. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 55 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 56 2.1. Terms and Definitions . . . . . . . . . . . . . . . . . . 4 57 3. Task Architecture . . . . . . . . . . . . . . . . . . . . . . 5 58 4. Task Architecture Elements . . . . . . . . . . . . . . . . . 7 59 5. Architecture Foundations . . . . . . . . . . . . . . . . . . 8 60 6. Task Extensions . . . . . . . . . . . . . . . . . . . . . . . 9 61 7. Task Specification . . . . . . . . . . . . . . . . . . . . . 9 62 7.1. CONCEPT for task type identification . . . . . . . . . . 10 63 7.2. Task Context and Relationships . . . . . . . . . . . . . 10 64 7.3. Task Domain Data Handling . . . . . . . . . . . . . . . . 10 65 8. Task Deadlines, Milestones and Time Planning . . . . . . . . 11 66 9. Task Scheduling and Assignment . . . . . . . . . . . . . . . 11 67 10. Status Reporting . . . . . . . . . . . . . . . . . . . . . . 12 68 10.1. Improved granularity in status reporting information . . 12 69 10.2. Relating reason and comments to ATTENDEE status 70 changes. . . . . . . . . . . . . . . . . . . . . . . . . 12 71 10.3. Comments associated to reasons and status changes . . . 12 72 10.4. Task Alerts and Notifications . . . . . . . . . . . . . 13 73 10.5. Automated Status Changes . . . . . . . . . . . . . . . . 14 74 11. New Parameter Values . . . . . . . . . . . . . . . . . . . . 14 75 11.1. Redefined VTODO Participant Status . . . . . . . . . . . 14 76 12. New Properties . . . . . . . . . . . . . . . . . . . . . . . 14 77 12.1. Estimated Duration . . . . . . . . . . . . . . . . . . . 14 78 12.2. Reason . . . . . . . . . . . . . . . . . . . . . . . . . 15 79 12.3. Sub-State . . . . . . . . . . . . . . . . . . . . . . . 16 80 12.4. Task Mode . . . . . . . . . . . . . . . . . . . . . . . 17 81 13. Property Extensions and Clarifications . . . . . . . . . . . 18 82 13.1. Redefined STATUS Property . . . . . . . . . . . . . . . 19 83 14. New Components . . . . . . . . . . . . . . . . . . . . . . . 19 84 14.1. Status Component . . . . . . . . . . . . . . . . . . . . 19 85 15. CalDAV Support for Task Mode . . . . . . . . . . . . . . . . 20 86 15.1. CALDAV:supported-task-mode-set Property . . . . . . . . 21 87 16. Security Considerations . . . . . . . . . . . . . . . . . . . 22 88 17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 89 17.1. Initialization of the Status registry . . . . . . . . . 22 90 17.2. Update of the Status registry . . . . . . . . . . . . . 22 91 17.3. Sub-State value registry . . . . . . . . . . . . . . . . 23 92 17.4. Task Mode value registry . . . . . . . . . . . . . . . . 23 93 17.5. Participation Statuses registry . . . . . . . . . . . . 24 94 17.6. Properties registry . . . . . . . . . . . . . . . . . . 24 95 18. Normative References . . . . . . . . . . . . . . . . . . . . 24 96 19. Informative References . . . . . . . . . . . . . . . . . . . 25 97 Appendix A. Examples of Task State Lifecycle . . . . . . . . . . 26 98 A.1. Simple Case Status Change . . . . . . . . . . . . . . . . 26 99 A.2. Example for multiple Attendees . . . . . . . . . . . . . 26 100 A.3. Example of Failure . . . . . . . . . . . . . . . . . . . 28 101 Appendix B. Change log . . . . . . . . . . . . . . . . . . . . . 28 102 Appendix C. Working Notes . . . . . . . . . . . . . . . . . . . 29 103 C.1. Advertising tasks . . . . . . . . . . . . . . . . . . . . 29 104 C.2. Subscribing to task updates . . . . . . . . . . . . . . . 29 105 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 107 1. Acknowledgements 109 The authors would like to thank the members of the Calendaring and 110 Scheduling Consortium technical committees and the following 111 individuals for contributing their ideas, support and comments: 113 John Chaffee, Marten Gajda, Ken Murchison 115 The authors would also like to thank CalConnect, the Calendaring and 116 Scheduling Consortium, for advice with this specification. 118 2. Introduction 120 This document specifies extensions to the existing Internet 121 Calendaring and Scheduling Core Object Specification (iCalendar) 122 [RFC5545], and associated protocols, in order to enhance the 123 structured communication and execution of tasks. The enhancements 124 allow for the communication, time planning and scheduling of tasks by 125 and between automated systems (e.g. in smart power grids, business 126 process management systems) as well as for human centered tasks. 128 A "task" is a representation of an item of work assigned to an 129 individual or organization. In the iCalendar Object Model [RFC5545] 130 the representation of tasks is by "VTODO" calendar components. Tasks 131 can be identified in a number of situations, either informally as ad- 132 hoc tasks in personal "to-do" lists or more formally in: 134 * Business processes - ranging from repetitive workflows to adaptive 135 cases and trouble ticketing 137 * Project Management - whether for large scale construction projects 138 or collaborative software development 140 The extensions specified here are defined in the context of an 141 overall architecture for task calendaring and scheduling. 143 2.1. Terms and Definitions 145 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 146 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 147 "OPTIONAL" in this document are to be interpreted as described in BCP 148 14 [RFC2119] [RFC8174] when, and only when, they appear in all 149 capitals, as shown here. 151 Terms defined in this specification include: 153 Assignee A calendar user assigned to perform a given task. An 154 assignee is equivalent to an attendee of an event. 156 Calendar User (CU) A person or software system that accesses or 157 modifies calendar information. 159 Calendar User Agent (CUA) This may be 161 1. Software with which the calendar user communicates with a 162 calendar service or local calendar store to access calendar 163 information. 165 2. Software that gathers calendar data on the Calendar User's 166 behalf. 168 Candidate A calendar user who might be able to perform a given task, 169 prior to actually being assigned the task, e.g., a dispatcher has 170 a list of taxi drivers (candidates) from which one will be 171 selected to pick-up a passenger. 173 Organizer A calendar user who creates a calendar item, requests 174 free/busy information, or published free/busy information. It is 175 an Organizer who invites Attendees [RFC5545]. 177 Observer A calendar user interested in a calendar component, e.g., a 178 manager may have interest in all tasks that have not been 179 completed. 181 Resource A resource in the scheduling context is any shared entity 182 that can be scheduled by a calendar user, but does not control its 183 own attendance status. Resources can be of "Location", 184 "Equipment", or "Role" type. 186 Task A representation of an item of work that can be assigned to one 187 or more task actor assignees. In [RFC5545], these are "VTODO" 188 calendar components, which are groupings of component properties 189 and possibly "VALARM" calendar components that represent an 190 action-item or assignment. 192 3. Task Architecture 194 A reference architecture for task calendaring and scheduling is 195 defined in order to identify the key logical elements involved in 196 task management and the interfaces between them to enable 197 interoperability. The logical elements identified here establish an 198 appropriate separation of concerns and clarify the responsibilities 199 of different elements. However, the architecture does not prescribe 200 a binding or packaging of elements, i.e., software systems may be 201 developed where some elements are tightly bound and the interfaces 202 between bound elements are not exposed. The task architecture is 203 also described in [TARCH]. 205 Task +-------+ 206 Trigger | 207 +---------------------V---------------------+ +-----------+ 208 | Task Generating System | | | 209 | +-------------------------+ | | | 210 | | O | | | | 211 | | /|\ | | | | 212 | | / \ | | | | 213 | | Task Organizer | <----> | 214 | +-^--------^--------------+ | | | 215 | | | | | | 216 | +--------V-+ +----V-----+ +----------+ | | | 217 | | Task | | Process | | Task | | | | 218 | |Assignment| | Logic <----> Domain | | | | 219 | | Rules | | | | Data | | | | 220 | +----------+ +----------+ +----------+ | | | 221 | | | | 222 +------^----------+-----^-------------------+ | | 223 | | | | | 224 Availability Task Task | | 225 | | Status | | 226 | | | | | 227 +------v----------v-----+-------------------+ | | 228 | Calendar and Scheduling System | | Directory | 229 | +---------+ +---------+ | | Service | 230 | | | | Task | <----> | 231 | |Schedule | | Lists | | | | 232 | | | | | | | | 233 | +---------+ +---------+ Server | | | 234 +-------------------------------------------+ | | 235 | Client | | | 236 | +----------------------+ +-----------+ | | | 237 | | Calendar | | Task | | | | 238 | | User Agent +----> Specific | <----> | 239 | | | |Application| | | | 240 | +----------------------+ +-----------+ | | | 241 | | | | 242 +-----^---------^--------+---------+--------+ | | 243 | | | | | | 244 +-----V---------V--------V---------V--------+ | | 245 | Task Actors | | | 246 | O O O O | | | 247 | /|\ /|\ /|\ /|\ +----> | 248 | / \ / \ / \ / \ | | | 249 | Candidate(s) Observer(s) | | | 250 | Assignee(s) Resource(s) | | | 251 +-------------------------------------------+ +-----------+ 253 4. Task Architecture Elements 255 The following logical elements form the task architecture that this 256 specification is based on: 258 Task Actors Various calendar users that may be involved in the 259 monitoring or performing of a task. The set of actors includes: 260 Organizers, Observers, Resources, Assignees, and Candidates. 262 Task Organizer The Organizer of a task. 264 Task Domain Data This is any domain specific data that may be acted 265 on or provides context to it in performing a task. 267 Task Specific Application A task specific application renders the 268 data concerning the task (including task domain data) for 269 presentation and manipulation by a task actor. 271 Process Logic Determines under what conditions a task (or tasks) is 272 generated and the actions to take on completion, or some other 273 status event occurring (or not) on the task. 275 Task Trigger This is some event that gives rise to the generation of 276 a task according to Process Logic. Task triggers can come from 277 many different sources including, for example; a task being 278 requested through the calendaring system, a status change in the 279 progression of a business process being managed by a business 280 process management or ERP system. 282 Task Assignment Rules Govern how actors are assigned to a task. A 283 range of different assignment patterns [WfRP] may be considered, 284 including the two general cases: 286 1. Delegation to a named actor or group of actors 288 2. Advertising to a pool of actors for self-selection 290 In either case the assignment may be made based on a variety of 291 criteria including, name, availability, skills, capacity, etc. 293 Task Generating System A system that creates and assigns tasks in 294 response to some initiating event (task trigger). Task creation 295 is according to Process Logic with task assignment determined by 296 Task Assignment Rules. This system also tracks the status of 297 tasks and will initiate further actions based upon the status. A 298 task generating system can take many forms, for example; Business 299 Process Management System, Project Management System, Bug Tracking 300 System, Building Control System. A Task Generating System may 301 also be a human. In iCalendar terms the Task Generating System is 302 the organizer. 304 Human Task Generation Task creation, assignment and tracking 305 coordinated by a human organizer is a special case of a task 306 generating system. In this case Task Assignment Rules and Process 307 Logic may be either explicit or tacit. 309 Directory Service A software system that stores and provides access 310 to information providing details of task actors that may 311 participate or be interested in a task. 313 Calendar and Scheduling System A software system that stores, 314 publishes and synchronizes calendar data such as events, tasks and 315 journal entries for actors. In the context of tasks this includes 316 schedules (i.e. allocated time and availability to perform tasks) 317 and task lists. A calendar and scheduling system typically 318 consists of server and client software components. 320 It is not within the scope of this document to specify how Process 321 Logic or Task Assignment Rules are codified. Such logic and rules 322 may be codified in a variety of ways, including traditional 323 programming languages (e.g. C++, Java) or process modelling 324 languages (e.g. BPMN [BPMN]). 326 5. Architecture Foundations 328 The key standards that enable interoperability between the logical 329 elements of the architecture are the Internet Calendaring and 330 Scheduling Core Object Specification (iCalendar) [RFC5545] and 331 associated protocols. Task and task status are represented by the 332 iCalendar "VTODO" component. Protocols include, in particular, the 333 iCalendar Transport-Independent Interoperability Protocol (iTIP) 334 [RFC5546] for task assignment and scheduling, and Calendaring 335 Extensions to WebDAV (CalDAV) [RFC4791] for client server 336 communication. 338 Additionally, this specification uses definitions from Support for 339 iCalendar Relationships [I-D.ietf-calext-ical-relations]. The LINK, 340 REFID, RELATED-TO and CONCEPT properties enable context and a rich 341 set of relationships between tasks and other iCalendar components to 342 be specified. 344 6. Task Extensions 346 In order to support the task architecture described in Section 3, 347 this document defines a number of extensions to the current iCalendar 348 standards in the areas of: 350 Task Specification improved ability to specify domain specific tasks 352 Task Deadlines, Milestones and Time Planning clarification of 353 deadlines and extension for task duration to support task time 354 planning 356 Task Scheduling and Assignment ensure support for common pattens of 357 scheduling and assigning tasks 359 Task Status Tracking improved granularity in status tracking 360 information and alerting task actors to pending or actual task 361 status changes 363 These extensions are supported mainly by additions to the properties 364 and parameters used within the "VTODO" component. 366 7. Task Specification 368 The specification of tasks must be semantically explicit in order for 369 them to be managed within the context of a business process or 370 project, and be understood by both humans and IT systems. The 371 current VTODO component only provides for simple ad-hoc tasks or 'to 372 do' lists, and is therefore extended by this specification as 373 follows: 375 Task type explicitly what type of task is to be performed is 376 identified. 378 Task context and relationships how a specific task relates to other 379 tasks and other objects that need to be understood for the 380 effective execution of a task. 382 Task specific data the form and content of domain data provided as 383 input to a task and/or that may be output from a task. 385 Organizer and attendee recognizes that a task organizer or attendee 386 can be an automated system. 388 7.1. CONCEPT for task type identification 390 The CONCEPT property is used to identify the type of task, for 391 example; 393 CONCEPT:http://example.com/task/delivery 395 7.2. Task Context and Relationships 397 The LINK property specifies a link to external information, which may 398 be context to the task. For example: 400 LINK;REL=SOURCE:http://example.com/package/1234567890 402 LINK;REL=describedby:mid:752142.1414823874.307E5@mx123.example.com 404 The external information may be data to be manipulated in performing 405 the task. See section 3.1.3 Task Domain Data Handling. 407 REFID is used to identify a key allowing the association of tasks 408 that are related to the same object and retrieval of a task based on 409 this key. This may be, for example, to identify the tasks associated 410 with a given project without having to communicate the task structure 411 of the project, or all tasks associated to a specific package. 413 REFID:Manhattan 415 REFID:1234567890 417 Extensions [Doug114] to the RELATED-TO property allow temporal 418 relationships between tasks as found in project management to be 419 specified as well as parent/child relationships and dependencies 420 (DEPENDS-ON). Tasks (VTODOs) may also be related to other calendar 421 components; for example to a VEVENT to block time to perform a task. 423 7.3. Task Domain Data Handling 425 Provide support for task specific input and output data (including 426 updates) beyond the standard iCalendar properties. It is envisaged 427 that standard calendar user agents will be able to launch task 428 specific applications by passing task specific data. 430 The LINK property can be used to 'attach' the domain specific data to 431 the task. For example, it might be a URI pointing to a web page 432 where the status of the task can be directly manipulated. 434 LINK;REL="vacation-system";VALUE=URI:http://example.com/ 435 vacation-approval?id=1234 437 Or it might be used for attachments specific to the task, for example 438 an electronic copy of a signature taken to confirm delivery of a 439 package. 441 LINK;REL="electronic-signature";VALUE=URI:http://example.com/ 442 delivery/sig1234.jpg 444 8. Task Deadlines, Milestones and Time Planning 446 Deadlines for starting and finishing a task are defined by the 447 DTSTART, DUE and DURATION properties. DTSTART represents the 448 earliest start time for beginning work on a task. DUE, or DTSTART + 449 DURATION represent the latest finish time for a task. Thus these 450 properties define a "window" within which a task has to be performed. 451 However, there is currently no way to indicate how long the task is 452 expected to take. This document defines a new property, ESTIMATED- 453 DURATION, to allow the estimated time that a task should take to be 454 specified separately from the deadlines for starting and finishing a 455 task. This supports time planning by enabling calendar user agents 456 to display when tasks should occur and therefore allow calendar users 457 to visualize when tasks should be performed and allocate time to 458 them. 460 A task that has intermediary deadlines (i.e., milestones) SHOULD be 461 expressed by child VTODO components (i.e., sub-tasks associated with 462 each of the milestones) in conjunction with the RELATED-TO property 463 to relate the parent and child tasks. 465 9. Task Scheduling and Assignment 467 This specification supports the two distinct models of assigning 468 actors to tasks, i.e., 1) strictly one assignee per task or 2) task 469 assignment to multiple assignees. In this regard one or many 470 ATTENDEES may be specified against a task depending upon the model 471 applied by the task organizer. 473 In addition a number of different patterns of resource or assignee 474 identification are anticipated. The specific Task Assignment Rules 475 are the responsibility of the Task Organizer. 477 Communication of task assignment or delegation to one or more actors 478 who are allocated to a task by the organizer is directly supported by 479 iTIP, i.e., all included ATTENDEES in an iTIP REQUEST are expected to 480 perform the task. 482 The offering or advertising of a task to one or more (potential) 483 actors where only one or a subset of the candidates may accept the 484 task will be addressed by a new VPOLL mode (See Appendix B) [VPOLL]. 486 10. Status Reporting 488 10.1. Improved granularity in status reporting information 490 This document defines a new status component that can be used to 491 group related information about the status. This might include 492 information on why (REASON) and when (DTSTAMP) a status has changed. 493 In addition new status values are specified to provide for task 494 suspension, failure and preparation. 496 10.2. Relating reason and comments to ATTENDEE status changes. 498 The [RFC9073] PARTICIPANT component can be used to provide additional 499 information about why an ATTENDEE participation status has changed. 500 The COMMENT property can also be used to include additional human 501 readable information about why the associated STATUS or ATTENDEE 502 property changed. 504 BEGIN:VSTATUS 505 STATUS:FAILED 506 REASON:http://example.com/reason/delivery-failed 507 SUBSTATE:ERROR 508 DTSTAMP:20130212T120000Z 509 COMMENT:Breakdown 510 END:VSTATUS 512 ATTENDEE;PARTSTAT=FAILED:mailto:xxx@example.com 513 ... 514 BEGIN:PARTICIPANT 515 CALENDAR-ADDRESS:mailto:xxx@example.com 516 DTSTAMP:20130226T1104510Z 517 REASON:http://example.com/reason/van-break-down 518 COMMENT:Puncture 519 END:PARTICIPANT 521 10.3. Comments associated to reasons and status changes 523 Multiple comments and reasons may have the same status. As 524 situations chnage further VSTATUS components can be added to provide 525 additional information.. 527 CONCEPT:http://example.com/task/delivery 528 BEGIN:VSTATUS 529 STATUS:FAILED 530 SUBSTATE:ERROR 531 DTSTAMP:20220212T104900Z 532 COMMENT:Out of time 533 END:VSTATUS 534 BEGIN:VSTATUS 535 STATUS:FAILED 536 COMMENT:Traffic Accident on E44 537 REASON:http://example.com/reason/traffic 538 DTSTAMP:20220212T110451Z 539 END:VSTATUS 540 BEGIN:VSTATUS 541 STATUS:FAILED 542 COMMENT:Arrived after office hours 543 REASON:http://example.com/reason/closed 544 DTSTAMP:20220212T180451Z 545 END:VSTATUS 547 10.4. Task Alerts and Notifications 549 Different needs to alert or notify task actors of pending or actual 550 task status changes are recognized: 552 Alarms Alarms (VLARM components) operate in the calendar user agent 553 space to notify the task actor of a pending task state for a task 554 they are assigned to or are interested in. Note: there is no 555 constraint in the current standards on the propagation of alarms 556 specified on calendar objects by organizers to individual 557 attendees. 559 Escalations An escalation or notification to the ATTENDEE, 560 ORGANIZER, or other task actor may be required if a deadline 561 associated with a task is exceeded or for some other reason. 562 Process Logic identifying when and who to propagate escalations to 563 is the responsibility of the Task Generating System, e.g., a BPMS. 565 Notifications Task actors (observers) not directly involved in 566 performing a task but with a known interest in a given task's 567 status can be identified by the ASSOCIATE property [Doug214] 568 against certain components e.g. ALARM, to identify which task 569 events the stakeholder/party is interested in. Notifications on 570 shared calendars will allow task actors to register an interest in 571 changes to tasks within a calendar (see Appendix A). 573 10.5. Automated Status Changes 575 A new property, TASK-MODE, is introduced to instruct servers to apply 576 automated operations for changing the status of a task. 578 11. New Parameter Values 580 11.1. Redefined VTODO Participant Status 582 Participant status parameter type values are defined in 583 Section 3.2.12 of [RFC5545]. This specification redefines that type 584 to include the new value FAILED for VTODO iCalendar components. 586 Format Definition This property parameter is extended by the 587 following notation: 589 partstat-todo /= *("FAILED") ; To-do cannot be completed 591 Example 593 ATTENDEE;REASON="http://example.com/reason/not-enough-time"; 594 PARTSTAT=FAILED:mailto:jsmith@example.com 596 12. New Properties 598 12.1. Estimated Duration 600 Property Name ESTIMATED-DURATION 602 Purpose This property specifies the estimated positive duration of 603 time the corresponding task will take to complete. 605 Value Type DURATION 607 Property Parameters IANA and non-standard property parameters can be 608 specified on this property. 610 Conformance This property can be specified in "VTODO" calendar 611 components. 613 Format Definition This property is defined by the following 614 notation: 616 est-duration = "ESTIMATED-DURATION" durparam ":" dur-value CRLF 617 ;consisting of a positive duration of time. 619 durparam = *(";" other-param) 620 Description In a "VTODO" calendar component the property MAY be used 621 to specify the estimated duration for the to-do, with or without 622 an explicit time window in which the event should be started and 623 completed. When present, DTSTART and DUE/DURATION represent the 624 window in which the task can be performed. ESTIMATED-DURATION 625 SHOULD be passed from ORGANIZER to ATTENDEE in iTIP [RFC5546] 626 messages. 628 Example The following is an example of this property that specifies 629 an interval of time of exactly one hour: 631 ESTIMATED-DURATION:PT1H 633 12.2. Reason 635 Property name REASON 637 Purpose To indicate the reason for a change in status of a task or 638 attendee participation status. 640 Value Type URI 642 Property Parameters IANA and non-standard property parameters can be 643 specified on this property. 645 Conformance This property can be specified in "VSTATUS" and 646 PARTICIPANT calendar components. 648 Format Definition This property is defined by the following 649 notation: 651 reason = "REASON" reasonparam ":" uri CRLF 653 reasonparam = *(";" other-param) 655 Description This property allows the change in status of a task or 656 participant status to be qualified by the reason for the change 657 with a codified reason. Typically reasons are defined within the 658 context of the task type and therefore SHOULD include the name- 659 space of the authority defining the task. Common reason codes are 660 IANA registered and do not have a name-space prefix. 662 Example 664 REASON:http://example.com/reason/delivered-on-time 666 REASON:out-of-office 668 12.3. Sub-State 670 Property name SUBSTATE 672 Purpose To provide additional granularity of task status for e.g. 673 IN-PROCESS. 675 Value Type TEXT 677 Property Parameters IANA and non-standard property parameters can be 678 specified on this property. 680 Conformance This property can be specified in a "VSTATUS" calendar 681 component. 683 Format Definition This property is defined by the following 684 notation: 686 substate = "SUBSTATE" substateparam ":" substatevalue CRLF 688 substateparam = *(";" other-param) 690 substatevalue = ("OK" ; everything is fine(the default) 691 / "ERROR" ; something is wrong (the REASON 692 ; code explains why) 693 / "SUSPENDED" ; waiting on some other task to 694 ; complete or availability of a 695 ; resource (REASON code explains 696 ; why) 697 / iana-token) ; Other IANA-registered type 699 Description The sub-state property allows additional qualification 700 and granularity of states to be recorded, in particular for the 701 IN-PROCESS state. It allows individual sub-states to be recorded 702 without the need to define and publish a sub-task associated with 703 a parent task purely to track that a particular state has been 704 reached. This property also allows parallel states to be 705 expressed e.g. that a task has been suspended at whatever state it 706 has reached. 708 Example 709 BEGIN:VSTATUS 710 STATUS:FAILED 711 REASON:http://example.com/reason/no-one-home 712 SUBSTATE:ERROR 713 END:VSTATUS 715 BEGIN:VSTATUS 716 STATUS:IN-PROCESS 717 REASON:http://example.com/reason/paint-drying 718 SUBSTATE:SUSPENDED 719 END:VSTATUS 721 12.4. Task Mode 723 Property Name TASK-MODE 725 Purpose This property specifies automatic operations that servers 726 apply to tasks based on changes in attendee status (PARTSTAT). 728 Value Type TEXT 730 Property Parameters IANA and non-standard property parameters can be 731 specified on this property. 733 Conformance This property can be specified zero or more times in a 734 "VTODO" calendar component. 736 Format Definition This property is defined by the following 737 notation: 739 task-mode = "TASK-MODE taskmodeparam ":" taskvalue 740 *("," taskvalue) CRLF 742 taskvalue = "AUTOMATIC-COMPLETION" ; set STATUS completed 743 ;if all attendees have completed 744 / "AUTOMATIC-FAILURE" 745 / "SERVER" 746 / "CLIENT" 747 / iana-token 748 / x-name 750 taskmodeparam = *(";" other-param) 752 Description In a "VTODO" calendar component this property MAY be 753 used to indicate to servers how they can automatically change the 754 state of the task based on iTIP replies from Attendees. For 755 example, the server can automatically set the overall task status 756 (STATUS) to COMPLETED when every attendee has marked their own 757 status (PARTSTAT) as COMPLETED, or the server could mark the task 758 as FAILED if its DUE date passes without it being completed. 759 TASK-MODE processing is performed on the organizer's copy of the 760 task. 762 The property value is a list of one or more IANA registered tokens 763 that defines modes to be used for the task. This specification 764 defines three modes which are described in the following sub- 765 sections. 767 Examples 769 TASK-MODE:AUTOMATIC-COMPLETION,AUTOMATIC-FAILURE 770 TASK-MODE:SERVER 771 TASK-MODE:AUTOMATIC-FAILURE 773 AUTOMATIC-COMPLETION Task Mode The task mode value "AUTOMATIC- 774 COMPLETION" indicates to the server that it can change the "VTODO" 775 component's STATUS property value to "COMPLETED" as soon as all 776 ATTENDEEs in the task have replied with a "PARTSTAT" parameter set 777 to "COMPLETED". 779 AUTOMATIC-FAILURE Task Mode The task mode value "AUTOMATIC-FAILURE" 780 indicates to the server that it SHOULD change the "VTODO" 781 component's STATUS property value to "FAILED" if either: 783 * the PARTSTAT of one ATTENDEE is set to FAILED; or 785 * the current time is past the effective due date of the 786 component and the task has not yet been completed. 788 Note: The effective due date is either the "DUE" property value or 789 the combination of the "DTSTART" and "DURATION" property values. 791 CLIENT Task Mode The task mode value "CLIENT" is an instruction to 792 the server to honour the status set by the client. 794 SERVER Task Mode The task mode value "SERVER" indicates to the 795 server that it can change the "VTODO" component's STATUS property 796 value to an appropriate value, based on implementation defined 797 "business rules", as ATTENDEE responses are processed or as 798 deadlines related to the task pass. 800 The server can add this property to a "VTODO" component to 801 indicate to the client that it will be managing the status. 803 13. Property Extensions and Clarifications 804 13.1. Redefined STATUS Property 806 The Status property is defined in Section 3.8.1.11 of [RFC5545]. 807 This specification extends that property to include new values 808 associated with VTODO iCalendar components (See Appendix A for 809 examples of the task state lifecycle). 811 Format Definition The "STATUS" property parameter list is augmented 812 as follows: 814 statvalue-todo = / "PENDING" ;Indicates a to-do has been 815 ;created and accepted, but has not 816 ;yet started. 817 / "FAILED" ;Indicates to-do has failed. 818 ;Extended status values for 819 ;"VTODO". 821 Description: 823 PENDING - A task has been created but has not yet started and is 824 ready to start subject to other dependencies (e.g. preceding task or 825 DTSTART). This is the default state. 827 FAILED - task has failed and may need some follow-up from the 828 organizer to re-schedule or cancel 830 Example: The following is an example of this property for a "VTODO" 831 calendar component: 833 STATUS:FAILED 835 14. New Components 837 14.1. Status Component 839 Component Name VSTATUS 841 Purpose This component allows information to be associated with a 842 status, for example comments and date stamps. 844 Conformance This component can be specified multiple times in any 845 appropriate calendar component. 847 Description This component provides a way for multiple date-stamped 848 statuses to be associated with a component such as a task or an 849 event. 851 This compoment may also be added to the [RFC9073] PARTICIPANT 852 component to allow participants in a task to specify their own 853 status. 855 Format Definition This component is defined by the following 856 notation: 858 statusc = "BEGIN" ":" "VSTATUS" CRLF 859 statusprop 860 "END" ":" "VSTATUS" CRLF 862 statusprop = *( 863 ; 864 ; The following is REQUIRED, 865 ; but MUST NOT occur more than once. 866 ; 867 status / 868 ; 869 ; The following are OPTIONAL, 870 ; but MUST NOT occur more than once. 871 ; 872 description / dtstamp / reason / substate / summary 873 ; 874 ; The following are OPTIONAL, 875 ; and MAY occur more than once. 876 ; 877 comment / styleddescription / iana-prop 878 ; 879 ) 881 Examples 883 BEGIN:VSTATUS 884 STATUS:COMPLETED 885 REASON: http://example.com/reason/delivered-on-time 886 DTSTAMP:20220212T120000Z 887 END:VSTATUS 889 15. CalDAV Support for Task Mode 891 The CalDAV [RFC4791] calendar access protocol allows clients and 892 servers to exchange iCalendar data. With the introduction of the 893 "TASK-MODE" property in this specification, different automated task 894 management behaviours may be delegated to the server by the Task 895 Organizer depending upon the value of "TASK-MODE". 897 In order for a CalDAV client to know what task modes are available, a 898 CalDAV server advertises a CALDAV:supported-task-mode-set WebDAV 899 property on calendar home or calendar collections if it supports the 900 use of the "TASK-MODE" property as described in this specification. 901 The server can advertise a specific set of supported task modes by 902 including one or more CALDAV:supported-task-mode XML elements within 903 the CALDAV:supported-task-mode-set XML element. If no 904 CALDAV:supported-task-mode XML elements are included in the WebDAV 905 property, then clients can try any task mode, but need to be prepared 906 for a failure when attempting to store the calendar data. 908 Clients MUST NOT attempt to store iCalendar data containing "TASK- 909 MODE" elements if the CALDAV:supported-task-mode-set WebDAV property 910 is not advertised by the server. 912 The server SHOULD return an HTTP 403 response with a DAV:error 913 element containing a CALDAV:supported-task-mode XML element, if a 914 client attempts to store iCalendar data with an "TASK-MODE" element 915 value not supported by the server. 917 It is possible for a "TASK-MODE" value to be present in calendar data 918 on the server being accessed by a client that does not support the 919 "TASK-MODE" property. It is expected that existing clients, unaware 920 of "TASK-MODE", will fail gracefully by ignoring the calendar 921 property. 923 15.1. CALDAV:supported-task-mode-set Property 925 Name supported-task-mode-set 927 Namespace urn:ietf:params:xml:ns:caldav 929 Purpose Enumerates the set of supported iCalendar "TASK-MODE" 930 element values supported by the server. 932 Protected This property MUST be protected and SHOULD NOT be returned 933 by a PROPFIND allprop request (as defined in Section 14.2 of 934 [RFC4918]). 936 Description See above. 938 Definition 940 941 942 944 Example 946 947 AUTOMATIC-COMPLETION 948 AUTOMATIC-FAILURE 949 SERVER 950 CLIENT 951 953 16. Security Considerations 955 This specification introduces no new security considerations beyond 956 those identified in [RFC5545]. 958 17. IANA Considerations 960 17.1. Initialization of the Status registry 962 This specification updates [RFC5545] by adding a Status value 963 registry to the iCalendar Elements registry and initializing it as 964 per [RFC5545]. 966 +==============+=========+===============================+ 967 | Name | Status | Reference | 968 +==============+=========+===============================+ 969 | CANCELLED | Current | Section 3.8.1.11 of [RFC5545] | 970 +--------------+---------+-------------------------------+ 971 | COMPLETED | Current | Section 3.8.1.11 of [RFC5545] | 972 +--------------+---------+-------------------------------+ 973 | CONFIRMED | Current | Section 3.8.1.11 of [RFC5545] | 974 +--------------+---------+-------------------------------+ 975 | DRAFT | Current | Section 3.8.1.11 of [RFC5545] | 976 +--------------+---------+-------------------------------+ 977 | FINAL | Current | Section 3.8.1.11 of [RFC5545] | 978 +--------------+---------+-------------------------------+ 979 | IN-PROCESS | Current | Section 3.8.1.11 of [RFC5545] | 980 +--------------+---------+-------------------------------+ 981 | NEEDS-ACTION | Current | Section 3.8.1.11 of [RFC5545] | 982 +--------------+---------+-------------------------------+ 983 | TENTATIVE | Current | Section 3.8.1.11 of [RFC5545] | 984 +--------------+---------+-------------------------------+ 986 Table 1: Initial Status Value Registry 988 17.2. Update of the Status registry 990 This specification further updates the Status registry with 991 additional values defined in this document. 993 +=========+=========+=========================+ 994 | Value | Status | Reference | 995 +=========+=========+=========================+ 996 | PENDING | Current | This Spec, Section 13.1 | 997 +---------+---------+-------------------------+ 998 | FAILED | Current | This Spec, Section 13.1 | 999 +---------+---------+-------------------------+ 1001 Table 2: Updated Status Value Registry 1003 17.3. Sub-State value registry 1005 The following table has been used to initialize the Sub-State 1006 registry. 1008 +===========+=========+=========================+ 1009 | Substate | Status | Reference | 1010 +===========+=========+=========================+ 1011 | OK | Current | This Spec, Section 12.3 | 1012 +-----------+---------+-------------------------+ 1013 | ERROR | Current | This Spec, Section 12.3 | 1014 +-----------+---------+-------------------------+ 1015 | SUSPENDED | Current | This Spec, Section 12.3 | 1016 +-----------+---------+-------------------------+ 1018 Table 3: Sub-State registry 1020 17.4. Task Mode value registry 1022 The following table has been used to initialize the Task Mode 1023 registry. 1025 +======================+=========+=========================+ 1026 | Task Mode | Status | Reference | 1027 +======================+=========+=========================+ 1028 | AUTOMATIC-COMPLETION | Current | This Spec, Section 12.4 | 1029 +----------------------+---------+-------------------------+ 1030 | AUTOMATIC-FAILURE | Current | This Spec, Section 12.4 | 1031 +----------------------+---------+-------------------------+ 1032 | CLIENT | Current | This Spec, Section 12.4 | 1033 +----------------------+---------+-------------------------+ 1034 | SERVER | Current | This Spec, Section 12.4 | 1035 +----------------------+---------+-------------------------+ 1037 Table 4: Task Mode Value Registry 1039 17.5. Participation Statuses registry 1041 The following table has been used to update the Participation 1042 Statuses registry. 1044 +========+=========+=========================+ 1045 | Value | Status | Reference | 1046 +========+=========+=========================+ 1047 | FAILED | Current | This Spec, Section 11.1 | 1048 +--------+---------+-------------------------+ 1050 Table 5: Participation Statuses Registry 1052 17.6. Properties registry 1054 The following table has been used to update the Properties registry. 1056 +====================+=========+=========================+ 1057 | Property | Status | Reference | 1058 +====================+=========+=========================+ 1059 | ESTIMATED_DURATION | Current | This Spec, Section 12.1 | 1060 +--------------------+---------+-------------------------+ 1061 | REASON | Current | This Spec, Section 12.2 | 1062 +--------------------+---------+-------------------------+ 1063 | SUBSTATE | Current | This Spec, Section 12.3 | 1064 +--------------------+---------+-------------------------+ 1065 | STATUS | Current | This Spec, Section 13.1 | 1066 +--------------------+---------+-------------------------+ 1067 | TASK-MODE | Current | This Spec, Section 12.4 | 1068 +--------------------+---------+-------------------------+ 1070 Table 6: Updated Properties Registry 1072 18. Normative References 1074 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1075 Requirement Levels", RFC 2119, RFC 2119, 1076 DOI 10.17487/RFC2119, March 1997, 1077 . 1079 [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, 1080 "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, 1081 RFC 4791, DOI 10.17487/RFC4791, March 2007, 1082 . 1084 [RFC4918] Dusseault, L., Ed., "HTTP Extensions for Web Distributed 1085 Authoring and Versioning (WebDAV)", RFC 4918, RFC 4918, 1086 DOI 10.17487/RFC4918, June 2007, 1087 . 1089 [RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and 1090 Scheduling Core Object Specification (iCalendar)", RFC 1091 5545, RFC 5545, DOI 10.17487/RFC5545, September 2009, 1092 . 1094 [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent 1095 Interoperability Protocol (iTIP)", RFC 5546, RFC 5546, 1096 DOI 10.17487/RFC5546, December 2009, 1097 . 1099 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1100 2119 Key Words", RFC 8174, RFC 8174, DOI 10.17487/RFC8174, 1101 May 2017, . 1103 [RFC9073] Douglass, M., "Event Publishing Extensions to iCalendar", 1104 RFC 9073, RFC 9073, DOI 10.17487/RFC9073, August 2021, 1105 . 1107 [I-D.ietf-calext-ical-relations] 1108 Douglass, M., "Support for iCalendar Relationships", I- 1109 D.ietf-calext-ical-relations, Work in Progress, Internet- 1110 Draft, ietf-calext-ical-relations, December 2020, 1111 . 1114 19. Informative References 1116 [BPMN] "Business Process Model and Notation", OMG BPMN 2.0.2, 1117 January 2014, 1118 . 1120 [TARCH] "Apthorp, A., Daboo, C., Douglass, M., CalConnect, Task 1121 Architecture V1.0,", CalConnect Task Architecture V1.0. 1123 [EDISTS] "UN Economic Commission for Europe, UN/EDIFACT, D14.A, STS 1124 STATUS, April 30, 1125 2014,http://www.unece.org/fileadmin/DAM/trade/untdid/d14a/ 1126 trsd/trsdsts.htm", UN/EDIFACT, D14.A. 1128 [WfRP] "Russell, N., ter Hofstede, A.H.M., Edmond, T., van der 1129 Aalst,W.M.P., Workflow Resource Patterns, Eindhoven 1130 University of Technology, 2004,", WfRP. 1132 [WSCal] "Considine, T., Douglass, M., WS-Calendar Version 1.0, 1133 OASIS, 30 July 2011,", OASIS WS-Calendar V1.0. 1135 [WSHT] "Ings, D., Clement, L., Koenig, D., Mehta, V., Mueller, 1136 R., Rangaswamy, R., Rowley, M., Trickovic, I., Web 1137 Services - Human Task Version 1.1 (WS-HumanTask), OASIS, 1138 17 August 2010,", OASIS WS-HT V1.1. 1140 Appendix A. Examples of Task State Lifecycle 1142 A.1. Simple Case Status Change 1144 +===+==============+==============+===========================+ 1145 | | STATUS | PARTSTAT | Action | 1146 +===+==============+==============+===========================+ 1147 | 1 | - | - | Organizer draft | 1148 +---+--------------+--------------+---------------------------+ 1149 | 2 | NEEDS-ACTION | NEEDS-ACTION | Organizer sends iTIP | 1150 | | | | request | 1151 +---+--------------+--------------+---------------------------+ 1152 | 3 | NEEDS-ACTION | ACCEPTED | Attendee reply | 1153 +---+--------------+--------------+---------------------------+ 1154 | 4 | PENDING | ACCEPTED | Task accepted but waiting | 1155 | | | | on some "trigger" to | 1156 | | | | start (e.g. another task | 1157 | | | | has to finish first) | 1158 +---+--------------+--------------+---------------------------+ 1159 | 5 | IN-PROCESS | IN-PROCESS | Attendee reply now | 1160 | | | | working on the task | 1161 +---+--------------+--------------+---------------------------+ 1162 | 6 | IN-PROCESS | COMPLETED | Attendee reply completed | 1163 +---+--------------+--------------+---------------------------+ 1164 | 7 | COMPLETED | COMPLETED | Organizer changes overall | 1165 | | | | state | 1166 +---+--------------+--------------+---------------------------+ 1168 Table 7: Example of status changes in assigning and 1169 performing a task with one attendee. 1171 A.2. Example for multiple Attendees 1173 Example of status changes in assigning and performing a task with two 1174 attendees (A1 and A2). 1176 +====+==============+==============+==============+================+ 1177 | | STATUS | PARTSTAT | PARTSTAT | Action | 1178 | | | (A1) | (A2) | | 1179 +====+==============+==============+==============+================+ 1180 | 1 | - | - | - | Organizer | 1181 | | | | | draft. | 1182 +----+--------------+--------------+--------------+----------------+ 1183 | 2 | NEEDS-ACTION | NEEDS-ACTION | NEEDS-ACTION | Organizer | 1184 | | | | | sends iTIP | 1185 | | | | | request. | 1186 +----+--------------+--------------+--------------+----------------+ 1187 | 4 | NEEDS-ACTION | ACCEPTED | NEEDS-ACTION | Attendee 1 | 1188 | | | | | reply. | 1189 +----+--------------+--------------+--------------+----------------+ 1190 | 5 | NEEDS-ACTION | ACCEPTED | ACCEPTED | Attendee 2 | 1191 | | | | | reply. | 1192 +----+--------------+--------------+--------------+----------------+ 1193 | 6 | PENDING | ACCEPTED | ACCEPTED | Task accepted | 1194 | | | | | but waiting on | 1195 | | | | | some"trigger" | 1196 | | | | | to start (e.g. | 1197 | | | | | another task | 1198 | | | | | has to finish | 1199 | | | | | first) | 1200 +----+--------------+--------------+--------------+----------------+ 1201 | 7 | IN-PROCESS | ACCEPTED | IN-PROCESS | Attendee 2 | 1202 | | | | | reply now | 1203 | | | | | working on the | 1204 | | | | | task. | 1205 +----+--------------+--------------+--------------+----------------+ 1206 | 8 | IN-PROCESS | IN-PROCESS | IN-PROCESS | Attendee 1 | 1207 | | | | | reply now | 1208 | | | | | working on the | 1209 | | | | | task. | 1210 +----+--------------+--------------+--------------+----------------+ 1211 | 9 | IN-PROCESS | COMPLETED | IN-PROCESS | Attendee 1 | 1212 | | | | | reply | 1213 | | | | | Completed | 1214 | | | | | (overall | 1215 | | | | | status still | 1216 | | | | | IN-PROCESS). | 1217 +----+--------------+--------------+--------------+----------------+ 1218 | 10 | IN-PROCESS | COMPLETED | COMPLETED | Attendee 2 | 1219 | | | | | reply | 1220 | | | | | Completed | 1221 +----+--------------+--------------+--------------+----------------+ 1222 | 11 | COMPLETED | COMPLETED | COMPLETED | Organizer | 1223 | | | | | changes | 1224 | | | | | overall state | 1225 | | | | | once both | 1226 | | | | | attendees are | 1227 | | | | | finished. | 1228 +----+--------------+--------------+--------------+----------------+ 1230 Table 8: Example for multiple Attendees 1232 Note: The logic for determining the status change to the VTODO is 1233 determined by the task organizer based on the ATTENDEE status and 1234 other business logic. 1236 A.3. Example of Failure 1238 Example of status changes for a task that fails. 1240 +===+==============+==============+==============================+ 1241 | | STATUS | PARTSTAT | Action | 1242 +===+==============+==============+==============================+ 1243 | 1 | - | - | Organizer draft | 1244 +---+--------------+--------------+------------------------------+ 1245 | 2 | NEEDS-ACTION | NEEDS-ACTION | Organizer sends iTIP request | 1246 +---+--------------+--------------+------------------------------+ 1247 | 3 | NEEDS-ACTION | ACCEPTED | Attendee reply | 1248 +---+--------------+--------------+------------------------------+ 1249 | 4 | IN-PROCESS | IN-PROCESS | Attendee reply now working | 1250 | | | | on the task | 1251 +---+--------------+--------------+------------------------------+ 1252 | 5 | IN-PROCESS | FAILED | Attendee reply task failed | 1253 +---+--------------+--------------+------------------------------+ 1254 | 6 | FAILED | FAILED | Organizer changes overall | 1255 | | | | state | 1256 +---+--------------+--------------+------------------------------+ 1258 Table 9: Example of Failure 1260 Appendix B. Change log 1262 V02. 2021-05-05 MD 1264 * Redo in asciidoc 1266 * Change STRUCTURED-CATEGORY to CONCEPT 1268 * Add GROUP parameter definition 1270 V01. 2015-08-23 AA 1271 * Highlighted use of ESTIMATED-DURATION for time planning. 1273 * Corrected PARTSTAT example section 5.1. Changed DECLINED to 1274 FAILED. 1276 * Replaced Task Mode AUTOMATIC-STATUS with CLIENT and SERVER modes. 1277 Also, clarified that task mode processing is only done on the 1278 organizer's copy. 1280 * Clarified responsibility for setting MODIFIED. 1282 * CalDAV support added. 1284 * Updated normative references. 1286 Appendix C. Working Notes 1288 C.1. Advertising tasks 1290 Use VPOLL for advertising a task to a pool of possible ATTENDEEs and 1291 then select the respondent to assign one or more assignees. 1293 Introduce POLL-MODE:ASSIGNMENT 1295 Need to indicate number of assignees required. 1297 Potentially different types of response e.g. ACCEPT or DECLINE, or a 1298 weighting e.g. 0 - 100 1300 Take into FREEBUSY discussion. 1302 C.2. Subscribing to task updates 1304 Stakeholders should have the ability to subscribe to categories / 1305 types of tasks on an ongoing basis. Reference calendarserver.org 1306 notifications draft 1308 Authors' Addresses 1310 Adrian Apthorp 1311 DHL Express 1312 Fritz-Erler-Str. 5 1313 Bonn 1314 Germany 1315 Email: adrian.apthorp@dhl.com 1316 Michael Douglass 1317 Bedework Commercial Services 1318 226 3rd Street 1319 Troy, NY 1320 United States of America 1321 Email: mdouglass@bedework.com