flasser

So my server is running minecraft version 1.16.5 with server software being Spigot. And when i start my server I get this error from the console, can anyone give me a guide on how to fix it? [12:28:31] [Server thread/ERROR]: Could not load 'plugins/SkBee.jar' in folder 'plugins' org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: com/shanebeestudios/skbee/SkBee has been compiled by a more recent version of the Java Runtime (class file version 60.0), this version of the Java Runtime only recognizes class file versions up to 55.0 at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:149) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:394) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:301) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at org.bukkit.craftbukkit.v1_16_R3.CraftServer.loadPlugins(CraftServer.java:381) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:224) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:928) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$0(MinecraftServer.java:273) ~[server.jar:3096-a-Spigot-9fb885e-af1a232] at java.lang.Thread.run(Thread.java:829) [?:?] Caused by: java.lang.UnsupportedClassVersionError: com/shanebeestudios/skbee/SkBee has been compiled by a more recent version of the Java Runtime (class file version 60.0), this version of the Java Runtime only recognizes class file versions up to 55.0 at java.lang.ClassLoader.defineClass1(Native Method) ~[?:?] at java.lang.ClassLoader.defineClass(ClassLoader.java:1017) ~[?:?] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174) ~[?:?]