New Outlook Content Forms: Migration options for custom form users

If you use custom forms in the classic version of Outlook, you may have noticed that the new Outlook for Windows does not support them in the same way. Custom forms are a powerful feature in classic Outlook, allowing organizations to create tailored data entry, approval, or tracking interfaces. The new Outlook replaces this with Content Forms, a different system based on SharePoint and Power Platform. This article explains the migration options available to custom form users, including what Content Forms can and cannot do, and the steps to transition your workflows.

What Content Forms Are and Why Classic Custom Forms Differ

Content Forms in the new Outlook are not a direct replacement for classic Outlook custom forms. Classic custom forms are stored in Outlook form libraries, use custom message classes, and can be published to public folders, organizational forms libraries, or personal form libraries. They support VBScript code behind the form, custom actions, and custom property pages.

Content Forms, by contrast, are SharePoint-based list forms that appear inside the new Outlook reading pane. They are defined using SharePoint list settings or Power Apps. They cannot run VBScript, do not support custom message classes, and cannot be tied to custom email item types. Content Forms only apply to SharePoint list items and certain Microsoft 365 list data sources.

The root cause of the incompatibility is architectural. The new Outlook is built on a web-based platform that does not load the classic Outlook form engine. Microsoft has no plan to bring the classic custom form engine to the new Outlook. Organizations that rely on custom forms must either adapt their workflows to Content Forms or continue using classic Outlook.

Prerequisites for Using Content Forms

To use Content Forms in the new Outlook, you need a SharePoint Online site or a Microsoft 365 list. The list must be added to the new Outlook as a pinned list or accessed through the SharePoint app. You also need permissions to create or edit SharePoint list forms. For Power Apps integration, a Power Apps license (Plan 1 or higher) is required for each user who will customize or use the forms.

Migration Options for Custom Form Users

You have three main migration paths. The choice depends on how complex your custom forms are and whether your organization can change its workflows.

Option 1: Replace Custom Forms with SharePoint List Forms

If your custom form is used to capture data that can be stored in a SharePoint list, this option works well. You create a SharePoint list with columns that match the fields in your custom form. Then you customize the SharePoint list form to match the layout and behavior of your original form.

1. Create a SharePoint list
   Go to your SharePoint site and create a new list. Add columns for each field in your custom form. Use choice columns for drop-downs, date columns for date pickers, and text columns for free text.
2. Customize the list form
   Open the SharePoint list, select Integrate > Power Apps > Customize forms. This opens Power Apps Studio with the default form. Add or rearrange fields. Set default values and validation rules using Power Apps formulas.
3. Pin the list to new Outlook
   In the new Outlook, select View > Lists. Find your SharePoint list and select Pin to Favorites. The list appears in the left navigation. When you click an item, the Content Form displays in the reading pane.
4. Test the form
   Create a new list item from the new Outlook and verify that all fields, validation, and dropdowns work as expected.

Option 2: Build a Power Apps Canvas App

For custom forms that involve complex logic, multiple data sources, or are not tied to a single SharePoint list, build a Power Apps canvas app. This app can be embedded in the new Outlook as a personal tab or add-in.

1. Create a canvas app in Power Apps
   Sign in to make.powerapps.com. Select Create > Canvas app. Choose a layout that matches your form’s purpose. Add data sources such as SharePoint, SQL Server, or Dataverse.
2. Replicate the custom form logic
   Add screens, controls, and formulas to replicate the behavior of your classic Outlook form. Use Power Apps functions like If, Switch, and Patch to handle conditional logic and data submission.
3. Publish and share the app
   Select File > Save > Publish to SharePoint. Share the app with users by sending them the app URL or adding it to a SharePoint site.
4. Add the app to new Outlook
   In the new Outlook, select View > Apps > Get Apps. Search for the app or add it manually using the app URL. The app appears in the Outlook ribbon or as a tab.

Option 3: Keep Using Classic Outlook

If your custom forms are deeply integrated into your business processes and cannot be easily replaced, continue using classic Outlook. Microsoft continues to support classic Outlook alongside the new Outlook. You can also run both versions on the same device. Set classic Outlook as the default mail app to ensure custom forms open automatically when you create or reply to items that use a custom message class.

What Content Forms Cannot Do and Workarounds

Content Forms Do Not Support VBScript or Custom Actions

Classic custom forms can run VBScript behind the form to automate tasks like sending emails, updating fields, or showing custom dialogs. Content Forms use Power Apps formulas, which are less powerful for Outlook-specific automation. Workaround: Move automation logic to Power Automate flows triggered by list item creation or modification.

Content Forms Cannot Be Tied to Custom Message Classes

In classic Outlook, a custom form is linked to a message class like IPM.Note.CustomName. When a user creates a new item using that class, the custom form loads automatically. Content Forms are tied to SharePoint list items only. Workaround: If you need a custom form for email items, you cannot use Content Forms. You must either stay on classic Outlook or redesign the process to use SharePoint lists.

Content Forms Do Not Work Offline

Classic custom forms are cached locally and work offline. Content Forms require an internet connection because they load from SharePoint. Workaround: There is no offline workaround for Content Forms. If offline access is critical, keep classic Outlook for those workflows.

Classic Custom Forms vs Content Forms: Key Differences

Item	Classic Custom Forms	Content Forms (New Outlook)
Form engine	Outlook form engine with VBScript	SharePoint list forms and Power Apps
Data source	Exchange mailboxes, public folders, Outlook items	SharePoint lists, Microsoft 365 lists
Custom code	VBScript, custom actions, property pages	Power Apps formulas and Power Automate
Offline support	Full offline cached mode	No offline support
Deployment	Publish to organizational forms library or public folder	SharePoint list settings or Power Apps sharing
Message class	Custom IPM classes for email, appointments, tasks	Not applicable — only list items

Conclusion

You now understand the three migration options for moving from classic Outlook custom forms to new Outlook Content Forms. The best path depends on your form complexity and data source. For simple data capture, SharePoint list forms work well. For complex logic, build a Power Apps canvas app. If your forms are tied to email items or require offline access, keep classic Outlook. Next, audit your existing custom forms using the classic Outlook Organizer’s Forms folder to inventory each form’s message class and functionality.