diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72763f74b..009970fa2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,11 +15,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * Added a field to specify the Context type that intent can return to the AppD Application schema and extended the findIntent API calls to be able to use it for resolution. ([#499](https://github.com/finos/FDC3/pull/499))
 * Added the ability to return a Channel from an intent (via the `IntentResult` type), resolver support for intents that return Channels and the concept of PrivateChannels. ([#508](https://github.com/finos/FDC3/pull/508))
 * Added error `UserCancelled` to the `ResolveError` enumeration to be used when user closes the resolver UI or otherwise cancels resolution of a raised intent ([#522 ](https://github.com/finos/FDC3/pull/522))
-* Added an `instanceId` (and optional `instanceMetadata`) field to `AppMetadata` allowing it to refer to specific app instances and thereby supporting targetting of intents to specific app instances. Also added a `findInstanes()` function to the desktop agent. ([#509]((https://github.com/finos/FDC3/pull/509))
+* Added an `instanceId` (and optional `instanceMetadata`) field to `AppMetadata` allowing it to refer to specific app instances and thereby supporting targetting of intents to specific app instances. Also added a `findInstances()` function to the desktop agent and `TargetAppUnavailable` and `TargetInstanceUnavailable` Errors to the `ResolveError` enumeration. ([#509]((https://github.com/finos/FDC3/pull/509))
 * Added a References and Bibliography section to the Standard's documentation to hold links to 'normative references' and other documentation that is useful for understanding the standard ([#530](https://github.com/finos/FDC3/pull/530))
 * `IntentResolution` now requires the name of the intent raised to included, allowing it to be used to determine the intent raised via `fdc3.raiseIntentForContext()`. ([#507](https://github.com/finos/FDC3/pull/507))
 * A Trademarks page was added to acknowledge trademarks used within the Standard not owned by FINOS or the Linux Foundation ([#534](https://github.com/finos/FDC3/pull/534))
 * Added details of FDC3's existing versioning and deprecation policies to the FDC3 compliance page ([#539](https://github.com/finos/FDC3/pull/539))
+* Add `IntentDeliveryFailed` to the `ResolveError` enumeration to be used when delivery of an intent and context to a targetted app or instance fails. ([#601](https://github.com/finos/FDC3/pull/601))
 
 ### Changed
 * Consolidated `Listener` documentation with other types ([#404](https://github.com/finos/FDC3/pull/404))
diff --git a/docs/api/ref/Errors.md b/docs/api/ref/Errors.md
index eb05d98bf..ad30be91a 100644
--- a/docs/api/ref/Errors.md
+++ b/docs/api/ref/Errors.md
@@ -8,10 +8,14 @@ Some FDC3 API operations return promises that can result in errors.
 
 ```typescript
 enum OpenError {
-  AppNotFound = "AppNotFound",
-  ErrorOnLaunch = "ErrorOnLaunch",
-  AppTimeout = "AppTimeout",
-  ResolverUnavailable = "ResolverUnavailable"
+  /** Returned if the specified application is not found.*/
+  AppNotFound = 'AppNotFound',
+  /** Returned if the specified application fails to launch correctly.*/
+  ErrorOnLaunch = 'ErrorOnLaunch',
+  /** Returned if the specified application launches but fails to add a context listener in order to receive the context passed to the `fdc3.open` call.*/
+  AppTimeout = 'AppTimeout',
+  /** Returned if the FDC3 desktop agent implementation is not currently able to handle the request.*/
+  ResolverUnavailable = 'ResolverUnavailable',
 }
 ```
 
@@ -24,12 +28,20 @@ Contains constants representing the errors that can be encountered when calling
 
 ```typescript
 export enum ResolveError {
+  /** SHOULD be returned if no apps are available that can resolve the intent and context combination.*/
   NoAppsFound = 'NoAppsFound',
+  /** Returned if the FDC3 desktop agent implementation is not currently able to handle the request.*/
   ResolverUnavailable = 'ResolverUnavailable',
+  /** Returned if the user cancelled the resolution request, for example by closing or cancelling a resolver UI.*/
   UserCancelled = 'UserCancelledResolution',
+  /** SHOULD be returned if a timeout cancels an intent resolution that required user interaction. Please use `ResolverUnavailable` instead for situations where a resolver UI or similar fails.*/
   ResolverTimeout = 'ResolverTimeout',
+  /** Returned if a specified target application is not available or a new instance of it cannot be opened. */
   TargetAppUnavailable = 'TargetAppUnavailable',
-  TargetInstanceUnavailable = 'TargetInstanceUnavailable'
+  /** Returned if a specified target application instance is not available, for example because it has been closed. */
+  TargetInstanceUnavailable = 'TargetInstanceUnavailable',
+  /** Returned if the intent and context could not be delivered to the selected application or instance, for example because it has not added an intent handler within a timeout.*/
+  IntentDeliveryFailed = 'IntentDeliveryFailed',
 }
 ```
 
@@ -45,7 +57,9 @@ Contains constants representing the errors that can be encountered when calling
 
 ```typescript
 enum ResultError {
+  /** Returned if the intent handler exited without returning a Promise or that Promise was not resolved with a Context or Channel object. */
   NoResultReturned = 'NoResultReturned',
+  /** Returned if the Intent handler function processing the raised intent throws an error or rejects the Promise it returned. */
   IntentHandlerRejected = 'IntentHandlerRejected',
 }
 ```
@@ -61,9 +75,12 @@ Contains constants representing the errors that can be encountered when calling
 
 ```typescript
 enum ChannelError {
-  NoChannelFound = "NoChannelFound",
-  AccessDenied = "AccessDenied",
-  CreationFailed = "CreationFailed"
+  /** Returned if the specified channel is not found when attempting to join a channel via the `joinUserChannel` function of the DesktopAgent (`fdc3`).*/
+  NoChannelFound = 'NoChannelFound',
+  /** SHOULD be returned when a request to join a user channel or to a retrieve a Channel object via the `joinUserChannel` or `getOrCreateChannel` methods of the DesktopAgent (`fdc3`) object is denied. */
+  AccessDenied = 'AccessDenied',
+  /** SHOULD be returned when a channel cannot be created or retrieved via the `getOrCreateChannel` method of the DesktopAgent (`fdc3`).*/
+  CreationFailed = 'CreationFailed',
 }
 ```
 
diff --git a/src/api/AppIntent.ts b/src/api/AppIntent.ts
index 1d294663c..57475ddcb 100644
--- a/src/api/AppIntent.ts
+++ b/src/api/AppIntent.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 import { AppMetadata } from './AppMetadata';
diff --git a/src/api/AppMetadata.ts b/src/api/AppMetadata.ts
index dd9a2ec7b..33c0c3591 100644
--- a/src/api/AppMetadata.ts
+++ b/src/api/AppMetadata.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 import { Icon } from './Icon';
diff --git a/src/api/Channel.ts b/src/api/Channel.ts
index b37d51971..bda96fe31 100644
--- a/src/api/Channel.ts
+++ b/src/api/Channel.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 import { Context } from '../context/ContextTypes';
diff --git a/src/api/DisplayMetadata.ts b/src/api/DisplayMetadata.ts
index 1c89ae8cc..e775a6145 100644
--- a/src/api/DisplayMetadata.ts
+++ b/src/api/DisplayMetadata.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 /**
diff --git a/src/api/Errors.ts b/src/api/Errors.ts
index 3a755e14a..c49881889 100644
--- a/src/api/Errors.ts
+++ b/src/api/Errors.ts
@@ -1,31 +1,50 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
+/** Constants representing the errors that can be encountered when calling the `open` method on the DesktopAgent object (`fdc3`). */
 export enum OpenError {
+  /** Returned if the specified application is not found.*/
   AppNotFound = 'AppNotFound',
+  /** Returned if the specified application fails to launch correctly.*/
   ErrorOnLaunch = 'ErrorOnLaunch',
+  /** Returned if the specified application launches but fails to add a context listener in order to receive the context passed to the `fdc3.open` call.*/
   AppTimeout = 'AppTimeout',
+  /** Returned if the FDC3 desktop agent implementation is not currently able to handle the request.*/
   ResolverUnavailable = 'ResolverUnavailable',
 }
 
+/** Constants representing the errors that can be encountered when calling the `findIntent`, `findIntentsByContext`, `raiseIntent` or `raiseIntentForContext` methods on the DesktopAgent (`fdc3`). */
 export enum ResolveError {
+  /** SHOULD be returned if no apps are available that can resolve the intent and context combination.*/
   NoAppsFound = 'NoAppsFound',
+  /** Returned if the FDC3 desktop agent implementation is not currently able to handle the request.*/
   ResolverUnavailable = 'ResolverUnavailable',
+  /** Returned if the user cancelled the resolution request, for example by closing or cancelling a resolver UI.*/
   UserCancelled = 'UserCancelledResolution',
+  /** SHOULD be returned if a timeout cancels an intent resolution that required user interaction. Please use `ResolverUnavailable` instead for situations where a resolver UI or similar fails.*/
   ResolverTimeout = 'ResolverTimeout',
+  /** Returned if a specified target application is not available or a new instance of it cannot be opened. */
   TargetAppUnavailable = 'TargetAppUnavailable',
+  /** Returned if a specified target application instance is not available, for example because it has been closed. */
   TargetInstanceUnavailable = 'TargetInstanceUnavailable',
+  /** Returned if the intent and context could not be delivered to the selected application or instance, for example because it has not added an intent handler within a timeout.*/
+  IntentDeliveryFailed = 'IntentDeliveryFailed',
 }
 
 export enum ResultError {
+  /** Returned if the intent handler exited without returning a Promise or that Promise was not resolved with a Context or Channel object. */
   NoResultReturned = 'NoResultReturned',
+  /** Returned if the Intent handler function processing the raised intent throws an error or rejects the Promise it returned. */
   IntentHandlerRejected = 'IntentHandlerRejected',
 }
 
 export enum ChannelError {
+  /** Returned if the specified channel is not found when attempting to join a channel via the `joinUserChannel` function  of the DesktopAgent (`fdc3`).*/
   NoChannelFound = 'NoChannelFound',
+  /** SHOULD be returned when a request to join a user channel or to a retrieve a Channel object via the `joinUserChannel` or `getOrCreateChannel` methods of the DesktopAgent (`fdc3`) object is denied. */
   AccessDenied = 'AccessDenied',
+  /** SHOULD be returned when a channel cannot be created or retrieved via the `getOrCreateChannel` method of the DesktopAgent (`fdc3`).*/
   CreationFailed = 'CreationFailed',
 }
diff --git a/src/api/Icon.ts b/src/api/Icon.ts
index 2d28fdf73..b19cfe7bb 100644
--- a/src/api/Icon.ts
+++ b/src/api/Icon.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 export interface Icon {
diff --git a/src/api/ImplementationMetadata.ts b/src/api/ImplementationMetadata.ts
index 3def6ecb3..ba68d867a 100644
--- a/src/api/ImplementationMetadata.ts
+++ b/src/api/ImplementationMetadata.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2021 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 /**
diff --git a/src/api/IntentMetadata.ts b/src/api/IntentMetadata.ts
index edc585add..41e7280ee 100644
--- a/src/api/IntentMetadata.ts
+++ b/src/api/IntentMetadata.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 /**
diff --git a/src/api/IntentResolution.ts b/src/api/IntentResolution.ts
index 1f3865744..9571f1af8 100644
--- a/src/api/IntentResolution.ts
+++ b/src/api/IntentResolution.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 import { IntentResult } from './Types';
diff --git a/src/api/Listener.ts b/src/api/Listener.ts
index 91f3de0b3..ced9e2e31 100644
--- a/src/api/Listener.ts
+++ b/src/api/Listener.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 export interface Listener {
diff --git a/src/api/Types.ts b/src/api/Types.ts
index b924529a7..c1ee70d16 100644
--- a/src/api/Types.ts
+++ b/src/api/Types.ts
@@ -1,6 +1,6 @@
 /**
  * SPDX-License-Identifier: Apache-2.0
- * Copyright 2019 FINOS FDC3 contributors - see NOTICE file
+ * Copyright FINOS FDC3 contributors - see NOTICE file
  */
 
 import { AppMetadata, Channel } from '..';