TrueLicense is commercial open source software covered by two licenses:
For open source software, TrueLicense is subject to the GNU AFFERO GENERAL PUBLIC LICENSE, Version 3. The AGPLv3 is a viral license, so you need to license your software under the same terms! At runtime, TrueLicense prints a notice telling your users that your software is subject to the AGPLv3 and that they need to have access to its source code for free.
For closed source software, you need to subscribe to the commercial licensing program for TrueLicense and buy one or more TrueLicense certificates. At runtime, if the signature of each certificate is found to be valid then no notice gets printed.