To make it easy to convert the old style of custom set, which made use of GAME Code, to the new style, which does not, I have added some code to populate the Custom Sets field with your GAME Code created custom set when you click on Run in Edit mode. All you have to do after clicking Run is to check that it looks accurate, delete your lines of GAME Code for creating a custom set, and switch your game to using the "Completely Custom set" in the Set Group called Custom.
This works appropriately only if you had a single custom set. If you had multiple custom sets for one game, then you probably know something about programming, and you can consult the documentation to figure out what to do.
To make it easy to convert the old style of custom set, which made use of GAME Code, to the new style, which does not, I have added some code to populate the Custom Sets field with your GAME Code created custom set when you click on Run in Edit mode. All you have to do after clicking Run is to check that it looks accurate, delete your lines of GAME Code for creating a custom set, and switch your game to using the "Completely Custom set" in the Set Group called Custom.
This works appropriately only if you had a single custom set. If you had multiple custom sets for one game, then you probably know something about programming, and you can consult the documentation to figure out what to do.