A Kai license is not perpetual, it is a timed subscription license. At the end of the subscription period you must renew your subscription license to continue using the software.
Kai is an add-on and requires an active license for RAD Studio, Delphi, or C++Builder to operate. Your Kai subscription is tied to the support and maintenance dates of your RAD Studio, Delphi, or C++Builder license. If your base product support or maintenance expires, Kai will no longer function. You would need to renew your base product support before Kai can be used again.