STAB 2.0.6 Error

20:25:36 [SEVERE] Could not load 'plugins\STAB.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError
: me/blackburn/STAB/Main : Unsupported major.minor version 51.0
        at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:150)
        at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.
java:305)
        at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager
.java:230)
        at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:207)
        at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:183)
        at net.minecraft.server.ServerConfigurationManager.<init>(ServerConfigur
ationManager.java:53)
        at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:156)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:422)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.UnsupportedClassVersionError: me/blackburn/STAB/Main : Unsu
pported major.minor version 51.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(Unknown Source)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$000(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.
java:41)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.
java:29)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:139)
        ... 8 more