# Licensing Old .NET Framework Applications

## Content



This topic applies to licensing .NET Framework 2.0 - 4.0 WinForms applications, .NET 3.5 - 4.0 WPF applications, and ComponentOne .NET 4.5.2 versions prior to 2020 v2. For .NET Framework 4.5.2+ see [Licensing .NET Framework Applications](/componentone/docs/license/online-license/licensing-applications/licensing-net-framework-applications).

Each developer or build machine needs an activated product serial key to build the project and properly license the application. To activate a serial key, see [Licensing Old Products with a New Serial Key](/componentone/docs/license/online-license/activation/licensing-old-controls-with-new-serial-key).

.Once you activate a serial key, most of the licensing process is handled automatically. Use the information below to better understand how the licensing works to help troubleshoot issues.

### Generating the Design-Time License File

ComponentOne .NET Framework controls support the standard licenses.licx file approach supported by the Microsoft .NET LicenseProvider. When you add a .NET Framework control to the Visual Studio designer surface, a design-time licenses.licx file is generated for the project. This file includes version information and must remain updated to reflect the version referenced in the application.

### Manually Generate the Design-Time License File

You can create the licenses.licx file manually if controls are added through code or XAML. For detailed steps, see [Generate licenses.licx File Manually](/componentone/docs/license/online-license/common-licensing-scenarios/generate-license-file-manually).

### Update the Design-Time License File

Use the MESCIUS Visual Studio extension to populate or update the licenses.licx file. Select Tools > MESCIUS > Update Projects.

Then your app can build and license the ComponentOne controls successfully. If you continue to see an unlicensed nag screen, see [Troubleshooting Old Licensing](/componentone/docs/license/online-license/Troubleshooting) topics.