diff --git a/types/office-js/index.d.ts b/types/office-js/index.d.ts
index 90c4583e67..11a14752ca 100644
--- a/types/office-js/index.d.ts
+++ b/types/office-js/index.d.ts
@@ -7369,19 +7369,14 @@ declare namespace Office {
             Base64 = "base64",
 
             /**
-             * The content of the attachment is returned as a string representing a url.
+             * The content of the attachment is returned as a string representing a URL.
              */
             Url = "url",
 
             /**
              * The content of the attachment is returned as a string representing an .eml formatted file.
              */
-            Eml = "eml",
-
-            /**
-             * The content of the attachment is returned as a string representing an .ical formatted file.
-             */
-            ICal
+            Eml = "eml"
         }
         /**
          * Specifies whether an attachment was added to or removed from an item.
@@ -8574,15 +8569,14 @@ declare namespace Office {
      */
     interface AttachmentContent {
         /**
-         * The content of an attachment in a string format.
+         * The content of an attachment as a string.
          */
         content: string;
         /**
          * The string format to use for an attachment's content.
          * For file attachments, the formatting is a base64-encoded string. 
          * For item attachments that represent messages, the formatting is a string representing an .eml formatted file. 
-         * For item attachments that represent calendar items, the formatting is an .ical file. 
-         * For cloud attachments, the formatting is a url string.
+         * For cloud attachments, the formatting is a URL string.
          */
         format: Office.MailboxEnums.AttachmentContentFormat;
     }
@@ -9422,10 +9416,6 @@ declare namespace Office {
          *
          * <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or read</td></tr></table>
          * 
-         * In addition to this signature, this method also has the following signature:
-         * 
-         * `getAsync(names: string[], options?: Office.AsyncContextOptions, callback?: (result: AsyncResult<Office.InternetHeaders>) => void): void;`
-         * 
          * @param names The names of the internet headers to be returned.
          * @param callback Optional. When the method completes, the function passed in the callback parameter is called with a single parameter, 
          *                 asyncResult, which is an Office.AsyncResult object.
@@ -9466,10 +9456,6 @@ declare namespace Office {
          *
          * <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose</td></tr></table>
          * 
-         * In addition to this signature, this method also has the following signature:
-         * 
-         * `removeAsync(names: string[], options?: Office.AsyncContextOptions, callback: (result: AsyncResult<Office.Body>) => void): void;`
-         * 
          * @param names The names of the internet headers to be removed.
          * @param callback Optional. When the method completes, the function passed in the callback parameter is called with a single parameter, 
          *                 asyncResult, which is an Office.AsyncResult object.
@@ -9517,10 +9503,6 @@ declare namespace Office {
          *
          * <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose</td></tr>
          *
-         * In addition to this signature, this method also has the following signatures:
-         * 
-         * `setAsync(headers: string, options?: Office.AsyncContextOptions, callback: (result: AsyncResult<void>) => void): void;`
-         * 
          * @param headers The names and corresponding values of the headers to be set. Should be a dictionary object with keys being the names of the 
          *                internet headers and values being the values of the internet headers.
          * @param callback Optional. When the method completes, the function passed in the callback parameter is called with a single parameter of type Office.AsyncResult.
@@ -9921,8 +9903,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -9948,8 +9930,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -10109,7 +10091,7 @@ declare namespace Office {
          */
         close(): void;
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          * 
          * [Api set: Mailbox Preview]
          *
@@ -10236,8 +10218,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -10270,8 +10252,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -10292,8 +10274,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -10317,8 +10299,8 @@ declare namespace Office {
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. 
          * In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -10339,8 +10321,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -10366,8 +10348,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -10652,7 +10634,7 @@ declare namespace Office {
      */
     interface AppointmentRead extends Appointment, ItemRead {
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          *
          * [Api set: Mailbox 1.0]
          *
@@ -10955,8 +10937,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -10983,8 +10965,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -11336,8 +11318,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -11363,8 +11345,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -11511,8 +11493,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -11539,8 +11521,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -11559,13 +11541,13 @@ declare namespace Office {
         addHandlerAsync(eventType: Office.EventType, handler: any, callback?: (result: AsyncResult<void>) => void): void;
 
         /**
-         * Gets an attachment from a message or appointment and returns it as an Office.AttachmentContent object.
+         * Gets an attachment from a message or appointment and returns it as an `Office.AttachmentContent` object.
          * 
-         * The getAttachmentContentAsync method gets the attachment with the specified identifier from the item. As a best practice, you should use 
+         * The `getAttachmentContentAsync` method gets the attachment with the specified identifier from the item. As a best practice, you should use 
          * the identifier to retrieve an attachment in the same session that the attachmentIds were retrieved with the `getAttachmentsAsync` or 
-         * `item.attachments` call. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. A session 
-         * is over when the user closes the app, or if the user starts composing an inline form and subsequently pops out the line form to continue 
-         * in separate window. 
+         * `item.attachments` call. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          * 
          * [Api set: Mailbox Preview]
          * 
@@ -11689,8 +11671,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -11717,8 +11699,8 @@ declare namespace Office {
        /**
         * Removes an event handler for a supported event.
         * 
-        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-        * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+        * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+        * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
         * 
         * [Api set: Mailbox 1.7]
         *
@@ -12039,7 +12021,7 @@ declare namespace Office {
          */
         close(): void;
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          * 
          * [Api set: Mailbox Preview]
          *
@@ -12144,8 +12126,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -12179,8 +12161,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -12201,8 +12183,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -12225,8 +12207,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -12518,7 +12500,7 @@ declare namespace Office {
      */
     interface ItemRead extends Item {
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          *
          * [Api set: Mailbox 1.0]
          *
@@ -13069,7 +13051,7 @@ declare namespace Office {
         /**
          * Sets the internet headers of a message.
          * 
-         * The internetHeaders property returns an InternetHeaders object that provides methods to set internet headers on the message.
+         * The internetHeaders property returns an InternetHeaders object that provides methods to manage the internet headers on the message.
          *
          * [Api set: Mailbox Preview]
          *
@@ -13320,8 +13302,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -13347,8 +13329,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -13510,7 +13492,7 @@ declare namespace Office {
          */
         close(): void;
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          * 
          * [Api set: Mailbox Preview]
          *
@@ -13641,8 +13623,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -13676,8 +13658,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -13698,8 +13680,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -13722,8 +13704,8 @@ declare namespace Office {
          * The removeAttachmentAsync method removes the attachment with the specified identifier from the item. 
          * As a best practice, you should use the attachment identifier to remove an attachment only if the same mail app has added that attachment 
          * in the same session. In Outlook Web App and OWA for Devices, the attachment identifier is valid only within the same session. 
-         * A session is over when the user closes the app, or if the user starts composing in an inline form and subsequently pops out the inline form 
-         * to continue in a separate window.
+         * A session is over when the user closes the app, or if the user starts composing an inline form then subsequently pops out the form to 
+         * continue in a separate window.
          *
          * [Api set: Mailbox 1.1]
          *
@@ -13744,8 +13726,8 @@ declare namespace Office {
         /**
          * Removes an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -13771,8 +13753,8 @@ declare namespace Office {
         /**
          * Removes an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -14057,7 +14039,7 @@ declare namespace Office {
      */
     interface MessageRead extends Message, ItemRead {
         /**
-         * Gets an array of attachments for the item.
+         * Gets the item's attachments as an array.
          *
          * [Api set: Mailbox 1.0]
          *
@@ -14168,7 +14150,7 @@ declare namespace Office {
         /**
          * Gets the internet headers of a message.
          * 
-         * The internetHeaders property returns an InternetHeaders object that provides a method to get the internet headers on the message.
+         * The internetHeaders property returns an InternetHeaders object that provides methods to manage the internet headers on the message.
          *
          * [Api set: Mailbox Preview]
          *
@@ -14392,8 +14374,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -14420,8 +14402,8 @@ declare namespace Office {
         /**
          * Adds an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -14777,8 +14759,8 @@ declare namespace Office {
         /**
          * Removes an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -14804,8 +14786,8 @@ declare namespace Office {
         /**
          * Removes an event handler for a supported event.
          * 
-         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.AttachmentsChanged` (Preview), 
-         * `Office.EventType.RecipientsChanged`, and `Office.EventType.RecurrenceChanged`.
+         * Currently the supported event types are `Office.EventType.AppointmentTimeChanged`, `Office.EventType.RecipientsChanged`, and 
+         * `Office.EventType.RecurrenceChanged`. In Preview, `Office.EventType.AttachmentsChanged` is also supported.
          * 
          * [Api set: Mailbox 1.7]
          *
@@ -16823,7 +16805,7 @@ declare namespace Office {
          */
         owner: String;
         /**
-         * The remote REST url related to the owner’s mailbox.
+         * The remote REST URL related to the owner’s mailbox.
          */
         restUrl: String;
         /**