Last modified: Feb 20, 2024

Migration from v3

How to migrate from App-frontend v3 to v4

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As of writing this documentation, the latest release candidate of app-frontend v4 is 4.0.0-rc3. Updated information is available on GitHub. Before the release of v4.0.0 stable, you will have to use exact version numbers in the URLs, e.g. 4.0.0-rc3 instead of 4. Each time we release a new release candidate and you want to try out the new release, this URL will have to be updated. When the stable version is released, you can use 4 as the version number in the URLs and get the latest stable version automatically.


This guide will help you migrate your app from using version 3 of App-frontend to version 4. Since there are several breaking changes between these versions, it is very important that you test your app thoroughly after migrating. There is currently no support in Altinn Studio for upgrading apps, so using the Altinn Studio CLI is the recommended way to migrate. This will fix most of the breaking changes automatically, but you may still need to make some manual changes to your code.

Migrate automatically using the Altinn Studio CLI

Note: You also need to upgrade the nuget packages to version 8.0. This can also be done using the Altinn Studio CLI. See Migration from v7 for more information.

The Altinn Studio CLI is a command line tool for upgrading Altinn Apps. The tool is able to upgrade and fix most breaking changes between version 3 and 4 of the Altinn App-frontend.

Verify that you have the latest version of the Altinn Studio CLI

If you do not have the CLI installed, you can install it by following the instructions in the installation guide.

Run the upgrade command

First, navigate to the root folder of your app in your terminal. There are several optional arguments you can use with the upgrade frontend command. You can see all the available options by running:

altinn-studio upgrade frontend --help

The default options should work for most apps, but you may need to specify some options if you have a non-standard project structure. If some of the options are not correct, the CLI should print an error message explaining what went wrong.

It is recommended to have a clean working tree before running the upgrade command. This means that you should commit or stash any changes you have made to your code before running the command. That way you can easily see what changes the CLI made to your code, as well as reset and try again if something went wrong.

When you are ready to upgrade, run the following command:

altinn-studio upgrade frontend

The CLI will then make the necessary changes to your code to upgrade it to version 4 of App-frontend. The CLI will also print warnings and errors if it encounters any problems during the upgrade process, make sure to read these carefully.

Migrate manually

To use App-frontend v4 in your app, you need to change which version is referenced in your app’s Index.cshtml file. This file should be located in the App/views/Home folder. In addition to changing the version, you should also remove the links to the third party CSS and font, as the font is now loaded by App-frontend itself, and the third party CSS is no longer used.

  1. Changes inside <head>:

      <title>@ViewBag.Org- @ViewBag.App</title>
      <link rel="icon" href="https://altinncdn.no/favicon.ico">
    - <!-- Third Party CSS -->
    - <link rel="stylesheet" href="https://altinncdn.no/toolkits/fortawesome/altinn-no-bold/0.1/css/embedded-woff.css">
    - <link rel="stylesheet" href="https://altinncdn.no/toolkits/fortawesome/altinn-no-regular/0.1/css/embedded-woff.css">
    - <link rel="stylesheet" href="https://altinncdn.no/toolkits/fortawesome/altinn-studio/0.1/css/embedded-woff.css">
    - <!-- Fonts -->
    - <link href="https://altinncdn.no/fonts/altinn-din/altinn-din.css" rel="stylesheet">
      <!-- Runtime CSS -->
    - <link rel="stylesheet" type="text/css" href="https://altinncdn.no/toolkits/altinn-app-frontend/3/altinn-app-frontend.css">
    + <link rel="stylesheet" type="text/css" href="https://altinncdn.no/toolkits/altinn-app-frontend/4.0.0-rc3/altinn-app-frontend.css">
  2. Changes inside <body>:

      <div class="flex-column d-flex media-body">
        function loadScript() {
          var appId = window.location.pathname.split('/');
          window.reportee = document.cookie.replace(/(?:(?:^|.*;\s*)AltinnPartyId\s*\=\s*([^;]*).*$)|^.*$/, "$1");;
          window.org = appId[1];
          window.app = appId[2];
      <div id="root" class="media-body flex-column d-flex"></div>
    - <script src="https://altinncdn.no/toolkits/altinn-app-frontend/3/altinn-app-frontend.js"></script>
    + <script src="https://altinncdn.no/toolkits/altinn-app-frontend/4.0.0-rc3/altinn-app-frontend.js"></script>
  3. It’s optionally also possible to change the $schema reference in layout files to get the latest suggestions and validations for layout configuration. This is not required for v4 to work, but is recommended when developing applications locally, as you’ll get the most up-to-date suggestions and validations in Visual Studio Code.

    -   "$schema": "https://altinncdn.no/schemas/json/layout/layout.schema.v1.json",
    +   "$schema": "https://altinncdn.no/toolkits/altinn-app-frontend/4.0.0-rc3/schemas/json/layout/layout.schema.v1.json",
        "data": {
          "layout": [
              "id": "nav1",
              "type": "NavigationBar"
  4. Fix any breaking changes affecting your app, including upgrading the nuget packages to version 8.0.