Bukkit Residence Errors

16:23:56 [SEVERE] Error occurred while enabling Residence v2.6.6 (Is it up to date?)
java.lang.NoSuchFieldError: COMMAND
at com.bekvon.bukkit.residence.protection.FlagPermissions.initValidFlags(FlagPermissions.java:184)
at com.bekvon.bukkit.residence.Residence.onEnable(Residence.java:283)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
at com.bekvon.bukkit.residence.Residence.setEnabled(Residence.java:546)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:374)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:270)
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:252)
at net.minecraft.server.MinecraftServer.i(MinecraftServer.java:298)
at net.minecraft.server.MinecraftServer.d(MinecraftServer.java:277)
at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:227)
at net.minecraft.server.DedicatedServer.init(DedicatedServer.java:140)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:378)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)