The invisible setting was removed as it was fairly pointless.
Two new options were added:
1. Accept friend requests - By default other players can request your friendship. If you uncheck the box, other players will no longer be able to do that.
This option is for the players who think they have too many friends already.

2. Auto accept friendship requests. By default it is not enabled. Once you enable it, it will automatically accept the friendship requests you receive and you will no longer receive a letter requesting you to accept or deny it.