As of v2020.1 of Catapult, temporary licenses for Muk3D need to be requested through Catapult. Once you've installed Catapult on your computer, you can request an evaluation (temporary) license by running Licensing/Request evaluation license.
This will generate an email with your login name and PC name, and this can be sent to email@example.com.
Once this email is received a temporary license will be created and sent back. Please note that licenses are generated in Calgary, Canada and will generally only be issued between 8am and 6pm MDT.
When you receive the temporary license, save it to the desktop and then drag & drop onto Catapult. You should see a confirmation dialog that the license was installed. Once successfully installed, you can delete the license file from your desktop. Please note that these licenses can only be installed in versions of Catapult v2020.1.1 or later.
If you encounter any difficulties please contact Muk3D support (firstname.lastname@example.org) before removing it. These licenses are single use and can not be reinstalled if removed.