# Licensing ActiveX and Legacy Products

## Content

This topic applies to licensing ActiveX, Silverlight and LightSwitch applications. For more options, see [Licensing Applications](/componentone/docs/license/online-license/licensing-applications).
Each developer or build machine needs an activated product serial key to build the project and properly license the application. The way to license an older product is determined by your serial key.
19 Digit Serial Key

* See [License Old Products with New Serial Key](/componentone/docs/license/online-license/activation/licensing-old-controls-with-new-serial-key).

17 or 28 Digit Serial Key

* See [Activating an Old Serial Key](/componentone/docs/license/online-license/activation/licensing-old-controls-with-new-serial-key).

Once you have an activated serial key that is valid for the ComponentOne version you are using, please refer to the platform documentation for application licensing information.

* [ActiveX Documentation](https://developer.mescius.com/componentone/docs/activex)
* [Silverlight Documentation](https://developer.mescius.com/componentone/docs/silverlight)
* [LightSwitch Documentation](https://developer.mescius.com/componentone/docs/lightswitch)