Getting a "your license key is outdated" message after angular upgrade

Hi,
We are on a process to migrate our project from Angular 8 to Angular 15. We're on Angular 10 now and while testing the Flexmonster component it is throwing a "Your license key is outdated and will not function with the current version" message. We haven't upgraded the Flexmonster library version and we're supposed to have the perpetual license, what may be the issue here?
Thanks