http://euw.leagueoflegends.com/en/news/game-updates/features/refer-friend-update-now-live

We started RAF to reward players for their part in growing League and we’ve updated the program to simultaneously remove incentives for abuse and better serve most League players. As we were working on the update, we found that the majority of League players refer between one and five friends.
The updated design now rewards you for bringing those friends into the game. With the new update, for every friend you refer who reaches level 10, you’ll earn 1000 IP. You can refer a total of five friends, and with three successful referrals, you’ll unlock the Grey Warwick skin. Recruit five friends and you’ll unlock Medieval Twitch.
There are no additional rewards to earn, and everyone who participated in Refer-a-Friend in the past have been transferred to the new program with the same number of referrals as before. For example, if you’ve already referred four friends, you’ll automatically earn 4000 IP and Grey Warwick. Please note, we’re also auto-redeeming unclaimed rewards for players who used previous versions of Refer-a-Friend, but this process could take a few days.
We’re excited to launch the update to the Refer-a-Friend program, head here to get started — good luck and have fun bringing your friends into League of Legends!

요약 :
1. 친구는 최대 5명까지 초대가능
2. 친구 레벨 10 달성시 1000ip 획득
3. 친구 3명 초대하면 회색 워윅 스킨 획득
4. 친구 5명 초대하면 중세 트위치 스킨 획득
5. 개편 전에 친구초대한사람은 개편후 의 기준으로 보상받음  
 (예) 친구초대시스템 개편전에 이미 4명의 친구를 초대했었다. 그러면 자동으로 4000ip 와 회색 워윅 스킨 받음