Good morning! By search on web I read that Facebook Like Button is now deprecated. There is an alternative? I would like to make a button that when user clicks on it, the app's Facebook page will be liked and the user rewarded with the app's coins. Is it possible? Thank you and sorry for my terrible English.
Incentivizing/Rewarding users is not allowed anymore. A few years ago, Facebook changed their policy about that:
4.4. Only incentivize a person to log into your app, enter a promotion on your app’s Page, check-in at a place, or to use Messenger to communicate with your business. Don’t incentivize other actions.
Withouth the user_likes permission, it is not possible to detect if a user liked some Page anymore anyway. And you would not get that permission approved in the neccessary review process for a use case that is not allowed, of course.