Follow these steps to update an existing extension within an OnTime desktop application:

1. Start OnTime Management Suite or OnTime Dispatch
2. Navigate to the Tools tab on the ribbon
3. Click the Install Extension button on the Tools tab of the ribbon
4. Locate the .OTEX file of the extension you wish to install and click Open
5. You will be prompted with a security warning about OnTime extensions. Click Yes if you wish to proceed with the installation of the extension
6. You will receive a message indicating whether or not the installation has been successful