diff --git a/types/office-js-preview/index.d.ts b/types/office-js-preview/index.d.ts
index 32719bafe9..6a5857604f 100644
--- a/types/office-js-preview/index.d.ts
+++ b/types/office-js-preview/index.d.ts
@@ -9573,6 +9573,124 @@ declare namespace Office {
              */
             Removed = "removed"
         }
+        /**
+         * Specifies the category color.
+         * 
+         * [Api set: Mailbox Preview]
+         * 
+         * @remarks
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        enum CategoryColor {
+            /**
+             * Default color
+             */
+            None,
+            /**
+             * Red
+             */
+            Red,
+            /**
+             * Orange
+             */
+            Orange,
+            /**
+             * Yellow
+             */
+            Yellow,
+            /**
+             * Green
+             */
+            Green,
+            /**
+             * Teal
+             */
+            Teal,
+            /**
+             * Olive
+             */
+            Olive,
+            /**
+             * Blue
+             */
+            Blue,
+            /**
+             * Purple
+             */
+            Purple,
+            /**
+             * Peach/Brown
+             */
+            Peach, // TODO: Confirm if this or Brown
+            /**
+             * Maroon/Cranberry
+             */
+            Maroon, // TODO: Confirm if this or Cranberry
+            /**
+             * Dark peach/Dark brown
+             */
+            DarkPeach, // TODO: Confirm if this or DarkBrown(Graph)
+            /**
+             * Dark maroon/Dark cranberry
+             */
+            DarkMaroon, // TODO: Confirm if this or DarkCranberry(Graph)
+            /**
+             * Steel
+             */
+            Steel,
+            /**
+             * Dark steel
+             */
+            DarkSteel,
+            /**
+             * Gray
+             */
+            Gray,
+            /**
+             * Dark gray
+             */
+            DarkGray,
+            /**
+             * Black
+             */
+            Black,
+            /**
+             * Dark red
+             */
+            DarkRed,
+            /**
+             * Dark orange
+             */
+            DarkOrange,
+            /**
+             * Dark yellow
+             */
+            DarkYellow,
+            /**
+             * Dark green
+             */
+            DarkGreen,
+            /**
+             * Dark teal
+             */
+            DarkTeal,
+            /**
+             * Dark olive
+             */
+            DarkOlive,
+            /**
+             * Dark blue
+             */
+            DarkBlue,
+            /**
+             * Dark purple
+             */
+            DarkPurple
+        }
         /**
          * Specifies an attachment's type.
          *
@@ -11875,6 +11993,21 @@ declare namespace Office {
          * </table>
          */
         body: Body;
+        /**
+         * Gets an object that provides methods for managing the item's categories.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         *
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Appointment Organizer</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        categories: Categories;
         /**
          * Gets or sets the date and time that the appointment is to end.
          *
@@ -12746,6 +12879,21 @@ declare namespace Office {
          * </table>
          */
         body: Body;
+        /**
+         * Gets an object that provides methods for managing the item's categories.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         *
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Appointment Attendee</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        categories: Categories;
         /**
          * Gets the date and time that an item was created.
          *
@@ -13515,6 +13663,21 @@ declare namespace Office {
          * </table>
          */
         body: Body;
+        /**
+         * Gets an object that provides methods for managing the item's categories.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         *
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        categories: Categories;
         /**
          * Gets the type of item that an instance represents.
          *
@@ -14898,6 +15061,21 @@ declare namespace Office {
          * </table>
          */
         body: Body;
+        /**
+         * Gets an object that provides methods for managing the item's categories.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         *
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Message Compose</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        categories: Categories;
         /**
          * Provides access to the Cc (carbon copy) recipients of a message. The type of object and level of access depends on the mode of the 
          * current item.
@@ -15739,6 +15917,21 @@ declare namespace Office {
          * </table>
          */
         body: Body;
+        /**
+         * Gets an object that provides methods for managing the item's categories.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         *
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Message Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        categories: Categories;
         /**
          * Provides access to the Cc (carbon copy) recipients of a message. The type of object and level of access depends on the mode of the 
          * current item.
@@ -17200,6 +17393,122 @@ declare namespace Office {
         removeHandlerAsync(eventType: Office.EventType, callback?: (asyncResult: Office.AsyncResult<void>) => void): void;
     }
 
+    /**
+     * Represents the categories on an item.
+     *
+     * [Api set: Mailbox Preview]
+     *
+     * @remarks
+     * <table>
+     *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+     *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+     * </table>
+     * 
+     * @beta
+     */
+    interface Categories {
+        /**
+         * Adds categories to an item. Each category name must be unique to that mailbox but multiple categories can use the same color.
+         *
+         * @param categories - The categories to be added to the item.
+         * @param options - Optional. An object literal that contains one or more of the following properties.
+         *        asyncContext: Developers can provide any object they wish to access in the callback method.
+         * @param callback - Optional. When the method completes, the function passed in the callback parameter is called with a single parameter of 
+         *                 type Office.AsyncResult.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadWriteItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        addAsync(categories: string[], options?: Office.AsyncContextOptions, callback?: (asyncResult: Office.AsyncResult<void>) => void): void;
+        /**
+         * Gets an item's categories.
+         *
+         * @param options - An object literal that contains one or more of the following properties.
+         *        asyncContext: Developers can provide any object they wish to access in the callback method.
+         * @param callback - When the method completes, the function passed in the callback parameter is called with a single parameter of 
+         *                 type Office.AsyncResult.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        getAsync(options: Office.AsyncContextOptions, callback: (asyncResult: Office.AsyncResult<void>) => void): void;
+        /**
+         * Gets an item's categories.
+         *
+         * @param callback - When the method completes, the function passed in the callback parameter is called with a single parameter of 
+         *                 type Office.AsyncResult.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        getAsync(callback: (asyncResult: Office.AsyncResult<void>) => void): void;
+        /**
+         * Removes categories from an item.
+         *
+         * @param categories - The categories to be removed from the item.
+         * @param options - Optional. An object literal that contains one or more of the following properties.
+         *        asyncContext: Developers can provide any object they wish to access in the callback method.
+         * @param callback - Optional. When the method completes, the function passed in the callback parameter is called with a single parameter of 
+         *                 type Office.AsyncResult.
+         *
+         * [Api set: Mailbox Preview]
+         *
+         * @remarks
+         * <table>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadWriteItem</td></tr>
+         *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+         * </table>
+         * 
+         * @beta
+         */
+        removeAsync(categories: string[], options?: Office.AsyncContextOptions, callback?: (asyncResult: Office.AsyncResult<void>) => void): void;
+    }
+
+    /**
+     * Represents the details of an item's category.
+     *
+     * [Api set: Mailbox Preview]
+     *
+     * @remarks
+     * <table>
+     *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/understanding-outlook-add-in-permissions | Minimum permission level}</td><td>ReadItem</td></tr>
+     *   <tr><td>{@link https://docs.microsoft.com/outlook/add-ins/#extension-points | Applicable Outlook mode}</td><td>Compose or Read</td></tr>
+     * </table>
+     * 
+     * @beta
+     */
+    interface CategoryDetails {
+        /**
+         * The name of the category. Maximum length is 255 characters.
+         */
+        displayName: string;
+        /**
+         * The color of the category.
+         */
+        color: Office.MailboxEnums.CategoryColor;
+    }
+
     /**
      * Represents a suggested meeting found in an item. Read mode only.
      *