New to Telerik UI for Blazor? Download free 30-day trial

How to Upgrade Telerik UI for Blazor

This article explains how to upgrade to a new version of Telerik UI for Blazor.

To upgrade the Telerik components, you need to update their NuGet package reference, and, if you use them, the CDN links.

The latest available version of UI for Blazor is 6.0.2.

Before starting an upgrade of your project, you may find it useful to review the following information:

  • Framework Versions Support - this will let you see what version of the .NET framework you need and which UI for Blazor versions work on it.
  • UI for Blazor Release History — reviewing the release notes for all releases you go through will let you see what has changed, what fixes, features and components have been implemented so you are better prepared to meet your project's challenges.
  • Whether you are affected by a breaking change. The List of Telerik UI for Blazor Versions with Breaking Changes article shows which releases of our component suite have breaking changes. Review the information for the releases you go through so you can evaluate whether you will be affected by anything.

In this article:

Upgrade Process

To upgrade the Telerik UI for Blazor components used in your project, perform the following steps:

  1. Make sure that you have a NuGet feed source with the version you want to upgrade to. This is usually the Telerik NuGet Feed, but you can also use a local feed from our MSI installer or ZIP archive.

  2. Update the version of the Telerik.UI.for.Blazor package your project references. If you are using a trial version, the package name is Telerik.UI.for.Blazor.Trial.

  3. If you are using the Telerik Blazor CDN, update the version in the theme URL. It must match the version of the package itself. For example, if you are upgrading to the 6.0.2 version, the CDN links must look like:


    <link rel="stylesheet" href="" />
    <script src="" defer></script>

    Generally, the URLs have the following format:


    <link rel="stylesheet" href="<VERSION NUMBER>/kendo-theme-<BUILT-IN-THEME>/all.css" />
    <script src="<VERSION NUMBER>/telerik-blazor.min.js" defer></script>
  4. If you are using a local theme stylesheet in wwwroot, then replace it. For example, if the app is using a custom theme, then recreate it with the ThemeBuilder. Or, if the project was created with the Telerik® UI for Blazor Visual Studio Extensions, then download the required built-in theme from the Telerik Blazor CDN and add it to the project.

  5. If the application is localized, update the Telerik localization (.resx) files. Otherwise you may see exceptions related to missing localization strings.

Upgrade Wizard

To upgrade the version of Telerik UI for Blazor you can use the Upgrade Wizard that comes as part of the Telerik UI for Blazor Visual Studio Extension.

Upgrade from Trial to Commercial

If you have just purchased a license and you need to migrate from the trial package to the licensed version, perform the following steps:

  1. Make sure that you have a NuGet feed source with the version you want to upgrade to. This is usually the Telerik NuGet Feed, but you can also use a local feed from our MSI installer or ZIP archive.

  2. Replace the reference to the Telerik.UI.for.Blazor.Trial package in your project with a reference to the Telerik.UI.for.Blazor package.

    • If you are referencing other Telerik trial packages that you now have a license for, remove the .Trial from their names too.
  3. If you are using static assets for our JS Interop file and/or Theme, update their path to match the package name (remove the .Trial part):


    <!-- FROM
    <script src="_content/Telerik.UI.for.Blazor.Trial/js/telerik-blazor.js" defer></script>
    <script src="_content/Telerik.UI.for.Blazor/js/telerik-blazor.js" defer></script>
    <!-- FROM
    <link rel="stylesheet" href="_content/Telerik.UI.for.Blazor.Trial/css/kendo-theme-default/all.css" />
    <link rel="stylesheet" href="_content/Telerik.UI.for.Blazor/css/kendo-theme-default/all.css" />

The Trial version of our assembly has the Telerik.Blazor Trial version Title. You can see it by Right clicking the assembly > Properties > File Description. You can find the assembly by extracting the .nupgk file like a .zip archive, or in the publish location.


Microsoft.JSInterop.JSException: Could not find ...

The most common problem you will encounter when upgrading is wrong references to our JS Interop file. You can read more about fixing them in the Troubleshoot JavaScript Errors article.

I Still See the Trial Watermark and Banner

While using a trial license, a watermark will be rendered over the components and you will see a banner with the following message:

Thank you for using the Trial Version of Telerik UI for Blazor to build more powerful applications faster. Purchase the Commercial Version now to get access to all product updates and the Telerik expert support.

If you have a commercial license, but you still see the trial watermark and banner, especially after publishing an app to a staging or live server, your build has used the trial Telerik.Blazor.dll assembly.

The most common reason for the problem is that the framework decides to incorrectly copy a trial version of our assembly into the dist folder of the app, even though it puts the correct licensed version at the root of the publish folder. This seems like a problem in the build process of the framework, and hopefully it will get fixed in future versions.

To fix this in the meantime, try the following process (you can try a new test build after each step where you make a change):

  1. Ensure that the licensed package is referenced in the project (Telerik.UI.for.Blazor instead of Telerik.UI.for.Blazor.Trial). Make sure this is also the case on the build machine. Sometimes a failed build or locked files may prevent a file from being updated and so the build machine may be using a trial reference.

  2. Uninstall any Trial installations from the build machine, dev PC and live server.

  3. If you have created local NuGet feeds, ensure they do not contain Trial versions of our packages.

  4. Clean the NuGet packages on the build machine, dev PC and live server.

  5. Clean the projects.

  6. Delete the bin and obj folders where packages and assemblies may be cached.

  7. Re-build your project.

See Also

In this article