Sony has although confirmed that about PlayStation 4 backwards compatibility with PS2 games using emulation and if you want to share downloads with family and friends, here we got an useful guide that help you do so following step-by-step instructions on how to share PS4 games with PlayStation Network.
Followed by a simply tutorial, using it you never need to get games shared with sing in with your account everytime and through it you can make PS4 the primary system for your account, and for that:
Getting this to work on the PS4 just requires you to activate it as the primary console. Now you need to log into PSN on your account on your friend or family member’s PS4.
1. Login with your account on your family/friend’s PS4 (PSN).
2. Go to the “Settings” tab.
3. Select PSN – Click on “Activate as Your Primary PS4“.
4. Click on Activate.
From here onwrads, they should be able to use your downloads on their PS4. They don’t have to login to your account to play your games or use your PS Plus. Why? Bceasue this does set the other person’s console as your primary PS4 and lets them play all your games.