Error Conlose

[18:07:02 INFO]: [ProjectKorra] Enabling ProjectKorra v1.6.0 BETA 7
[18:07:03 INFO]: [ProjectKorra] [ProjectKorra] Establishing SQLite Connection.[S
QLite] Connection established!
[18:07:03 ERROR]: Error occurred while enabling ProjectKorra v1.6.0 BETA 7 (Is i
t up to date?)
java.lang.NoSuchMethodError: org.bukkit.Bukkit.getOnlinePlayers()Ljava/util/Coll
ection;
        at com.projectkorra.ProjectKorra.ProjectKorra.onEnable(ProjectKorra.java
:52) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:250) ~[s
pigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader
.java:324) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManage
r.java:405) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at org.bukkit.craftbukkit.v1_7_R2.CraftServer.loadPlugin(CraftServer.jav
a:462) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at org.bukkit.craftbukkit.v1_7_R2.CraftServer.enablePlugins(CraftServer.
java:380) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.MinecraftServer.n(MinecraftServer.java:3
53) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.MinecraftServer.g(MinecraftServer.java:3
28) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.MinecraftServer.a(MinecraftServer.java:2
84) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.DedicatedServer.init(DedicatedServer.jav
a:186) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.MinecraftServer.run(MinecraftServer.java
:442) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
        at net.minecraft.server.v1_7_R2.ThreadServerApplication.run(SourceFile:6
18) [spigot-1.7.5-spigot-1.7.5-R0.1-SNAPSHOT.jar:git-Spigot-1387]
[18:07:03 INFO]: Server permissions file permissions.yml is empty, ignoring it
[18:07:03 INFO]: Done (3.090s)! For help, type "help" or "?"