Error RPG Skills 1.8.8

10.10 20:20:54 [Multicraft] Skipped 14 lines due to rate limit (30/s)
10.10 20:20:54 [Server] INFO at me.deadlyscone.main.RPGSkills.onEnable(RPGSkills.java:147) ~[?:?]
10.10 20:20:54 [Server] INFO at me.deadlyscone.main.ConfigParser.scanFiles(ConfigParser.java:49) ~[?:?]
10.10 20:20:54 [Server] INFO java.lang.NoSuchMethodError: java.nio.file.Files.readAllLines(Ljava/nio/file/Path;)Ljava/util/List;
10.10 20:20:54 [Server] ERROR Error occurred while enabling RPGSkills v3.4.0b (Is it up to date?)