Stay safe, code ethically, and remember: If a script claims to be "KAT" and "no key" on a forum—someone has already left the backdoor open for themselves.
The last genuine KAT code commit was before 2016. PHP has evolved from version 5.6 to 8.x. Your stack will be incompatible with modern PHP, forcing you to use obsolete, unpatched versions of MySQL and Apache. When a new vulnerability like Log4Shell or CVE-2023-3824 emerges, you remain exposed forever because no community maintains the "no key" script.