Hi,

The button is not unlocked when you add the mod in an existing save that already has circuit network unlocked.

You need to do a migration file that look if circuit network is already unlocked and if it is add unlock the recipe by hand.

http://lua-api.factorio.com/latest/Migrations.html
http://kovarex.com/wiki/index.php?title=Migration_scripts

you can look in the game folder for more example
Factorio_0.16.20\data\base\migrations

Thanks for the advice mate and the information of the links, much appreciated :)

In the next version, I will create the required file and functions to migrate the recipes if they have the technologies already investigated in an existing game save.

Also I will add a new operation option, this will be enabled / disabled in the game / option / controls / Mods, and I hope it will be well received.

I have added the corresponding code to allow the migration of recipes to games already saved, I hope it works well, if not, I would appreciate any report of failures