Lingon is a rip-off project. There have been no changes in the Launchagent/daemon system for 10+ years, Lingon never supported all features and still asks for yearly upgrades. The tool of choice for these kinds of tasks is the way better "LaunchControl".
What would be this new implementation which keeps us from using it if not under 10.13? since v3 it's always been same story, new system new lingon? are you kidding right? there is no actual reason for this... but to force the customer buying a new one.. since actual licenses can be used for older version but i doubt that v5 lic. will be any good on this v6 release, GREED is the word to describe such kind of behaviour. As many devs now have put in place such a kind of policy... simply disgusting. Sometimes i'm really glad to see many of those apps pirated... its just what you deserve.