Plugin Help Unable to install McMMO

Tried installing mcmmo on a spigot 1.1 server.

Got this error:

[01:43:47 INFO]: [mcMMO] Enabling mcMMO v1.5.00-b3547 [01:43:48 ERROR]: [mcMMO] There was an error while enabling mcMMO! [01:43:48 WARN]: java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()[Lorg/bukkit/entity/Player; [01:43:48 WARN]: at com.gmail.nossr50.mcMMnEnable(mcMMO.java:163) [01:43:48 WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271) [01:43:48 WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [01:43:48 WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [01:43:48 WARN]: at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:375) [01:43:48 WARN]: at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:325) [01:43:48 WARN]: at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:205) [01:43:48 WARN]: at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:542) [01:43:48 WARN]: at java.lang.Thread.run(Thread.java:745) [01:43:48 INFO]: [mcMMO] Disabling mcMMO v1.5.00-b3547 [01:43:48 ERROR]: Error occurred while disabling mcMMO v1.5.00-b3547 (Is it up to date?)

 

"java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()[Lorg/bukkit/entity/Player;"

This NSME usually occurs with plugins that aren't updated for 1.9+. I'm assuming you're trying to use McMMo 1.8 on a 1.11 server.