[심각] Could not load 'plugins\uSkyBlock(1.5.2).jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: us/talabrek/ultimateskyblock/utils/command/CommandManager$RequirementChecker : Unsupported major.minor version 52.0                                                                                   at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
        at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:306)
        at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
        at org.bukkit.craftbukkit.v1_5_R3.CraftServer.loadPlugins(CraftServer.java:241)
        at org.bukkit.craftbukkit.v1_5_R3.CraftServer.<init>(CraftServer.java:219)
        at net.minecraft.server.v1_5_R3.PlayerList.<init>(PlayerList.java:55)
        at net.minecraft.server.v1_5_R3.DedicatedPlayerList.<init>(SourceFile:11)
        at net.minecraft.server.v1_5_R3.DedicatedServer.init(DedicatedServer.java:93)
        at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:388)
        at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.UnsupportedClassVersionError: us/talabrek/ultimateskyblock/utils/command/CommandManager$RequirementChecker : Unsupported major.minor version 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        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$100(Unknown Source)
        at java.net.URLClassLoader$1.run(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.findClass0(PluginClassLoader.java:80)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.defineClass1(Native Method)
        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$100(Unknown Source)
        at java.net.URLClassLoader$1.run(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.findClass0(PluginClassLoader.java:80)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
        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.java:173)
        ... 9 more

이쪽이 문제를 나타내는부분인것 같은데 해결책을 도통 모르겠네요.. 알려주시면 감사하겠습니다 ㅠㅠㅠ