[10:48:28] [Server thread/ERROR]: Could not load 'plugins/PirateSK-0.4.1.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: pl/piratjsk/piratesk/PirateSK : Unsupported major.minor version 52.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at org.bukkit.craftbukkit.v1_8_R1.CraftServer.loadPlugins(CraftServer.java:290) [serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at net.minecraft.server.v1_8_R1.DedicatedServer.init(DedicatedServer.java:152) [serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:494) [serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at java.lang.Thread.run(Unknown Source) [?:1.7.0_55]
Caused by: java.lang.UnsupportedClassVersionError: pl/piratjsk/piratesk/PirateSK : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.7.0_55]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.7.0_55]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[?:1.7.0_55]
at java.net.URLClassLoader.defineClass(Unknown Source) ~[?:1.7.0_55]
at java.net.URLClassLoader.access$100(Unknown Source) ~[?:1.7.0_55]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_55]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_55]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_55]
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.7.0_55]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_55]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_55]
at java.lang.Class.forName0(Native Method) ~[?:1.7.0_55]
at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_55]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[serwer33735.jar:git-Spigot-b1e6da1-17962f6]