Frequently Asked Questions About Installing Telerik License Key
This article lists the answers to the most frequently asked questions (FAQs) about working with the Telerik UI for WPF license key.
Does the license key expire?
Yes, the license key expires at the end of your support subscription:
For trial users, this is at the end of your 30-day trial.
For commercial license holders, this is when your subscription term expires.
You will need to obtain and install a new license key after starting a trial, renewing a license, or upgrading a license.
An expired perpetual license key is valid for all Telerik UI for WPF versions published before its expiration date.
Will the product function with an expired license key?
This depends on your license type.
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Perpetual licenses will continue to function normally with an expired license key. However, the following will happen if you update or install a package version which is released after the expiration date of the license:
- A watermark appears on application startup.
- A modal dialog appears on application startup.
- A warning message is logged in the build log.
See the Invalid License section for more information.
Subscription licenses will prevent you from building the application with an expired license key. Deployed applications will continue to function normally.
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Trial licenses will prevent the applications from functioning normally once the trial period has expired. The following will happen if you try to build or run the application:
- A watermark appears on application startup.
- A modal dialog appears on application startup.
- A warning message is logged in the build log.
See the Invalid License section for more information.
I updated the version of the UI for WPF packages in my project and the invalid license errors have appeared. What is the cause of this behavior?
The most likely cause is that the newly installed Telerik UI for WPF components were released after the expiration date of your current license. To fix this issue:
Activate the new license key in your project.
Can I use the same license key in multiple builds?
You can use your personal license key in multiple pipelines, builds, and environments.
However, each individual developer must use a unique personal license key.
Do I need an Internet connection to activate the license?
No, the license activation and validation are performed entirely offline.
Do I have to add the license key to source control?
No, you do not have to add the telerik-license.txt license key file or its contents to source control.
Build servers must use the TELERIK_LICENSE environment variable described in Adding the License Key to CI Services.
Do not store the license key in plaintext, for example, in a GitHub Actions Workflow definition.
What happens if both the environment variable and the license key file are present?
If both the TELERIK_LICENSE environment variable and the telerik-license.txt file are present, then the environment variable will be used.
To enforce the use of the license key file, unset the environment variable.
My team has more than one license holder. Which key do we have to use?
To activate Telerik UI for WPF on your development machine, use the key associated with your personal account.
To activate Telerik UI for WPF in a CI/CD environment, use any of the license keys in your team.
Are earlier versions of Telerik UI for WPF affected?
No, versions released prior to January 2025 (Q1) do not require a license key.