Skip to content

outlook-requirement-set-preview.md

Latest commit

 

History

History
52 lines (35 loc) · 4.59 KB

outlook-requirement-set-preview.md

File metadata and controls

52 lines (35 loc) · 4.59 KB
Raw
title Outlook add-in API preview requirement set
description Features and APIs that are currently in preview for Outlook add-ins.
ms.date 07/30/2026
ms.topic whats-new
ms.localizationpriority medium

Outlook add-in API preview requirement set

The Outlook add-in API subset of the Office JavaScript API includes objects, methods, properties, and events that you can use in an Outlook add-in.

Preview APIs are subject to change and aren't intended for use in a production environment. We recommend that you try them out in test and development environments only. Don't use preview APIs in a production environment or within business-critical documents.

To use preview APIs:

  • You must use the preview version of the Office JavaScript API library from the Office.js content delivery network (CDN). The type definition file for TypeScript compilation and IntelliSense is found at the CDN and DefinitelyTyped. You can install these types with npm install --save-dev @types/office-js-preview (be sure to remove the types for @types/office-js if you've previously installed them).

  • You may need to join the Microsoft 365 Insider program for access to more recent Office builds in Outlook on Windows and on Mac.

  • You may need to configure the Targeted release option on your Microsoft 365 tenant to preview features in Outlook on the web. For more information, see the "Targeted release" section of Set up the Standard or Targeted release options.

The preview requirement set includes all of the features of requirement set 1.15.

Important

This documentation is for a preview requirement set. This requirement set isn't fully implemented yet, and clients won't accurately report support for it. You shouldn't specify this requirement set in your add-in manifest.

Features in preview

The following features are in preview.

  • Added the ability to decrypt Outlook item attachments (Office.MailboxEnums.AttachmentType.Item) in an encryption add-in. To learn more, see Decrypt Outlook item attachments (preview).
  • Added a property to the event.completed method of encryption add-ins to display a custom error message when decryption fails. To learn more, see Customize error messages for the decryption operation (preview).
  • Added a property to the event.completed method of encryption add-ins to restrict printing, copying, and saving of decrypted content. To learn more, see Manage distribution of decrypted content (preview).
  • Added a Retry action to the decryption timeout notification in encryption add-ins so recipients can retry a failed decryption operation without switching to another message.
  • Extended support for the errorMessageMarkdown property of the event.completed method to Smart Alerts add-ins in Outlook on Mac.
  • Added a property to get or set whether an appointment is an all-day event.
  • Added events to activate an event-based add-in on a message in read mode when it contains certain attachment types or custom internet headers.
  • Added a property and objects to temporarily set the body or subject displayed in read mode.

API list

The following table lists the Outlook JavaScript APIs currently in preview. To view API reference documentation for all Outlook JavaScript APIs (including preview APIs and previously released APIs), see Outlook APIs.

[!INCLUDE outlook-preview]

See also