soundmuffler deth

[22:43:58] [Server thread/INFO]: [SoundMuffler] Enabling SoundMuffler vDEV - 20 (git cde78980)
[22:43:58] [Server thread/ERROR]: Error occurred while enabling SoundMuffler vDEV - 20 (git cde78980) (Is it up to date?)
java.lang.NoClassDefFoundError: me/mrCookieSlime/Slimefun/Objects/SlimefunItem/UnregisterReason
	at dev.j3fftw.soundmuffler.SoundMufflerMachine.<init>(SoundMufflerMachine.java:123) ~[?:?]
	at dev.j3fftw.soundmuffler.SoundMuffler.onEnable(SoundMuffler.java:34) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[patched_1.16.5.jar:git-Paper-629]
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:380) ~[patched_1.16.5.jar:git-Paper-629]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:483) ~[patched_1.16.5.jar:git-Paper-629]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugin(CraftServer.java:501) ~[patched_1.16.5.jar:git-Paper-629]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugins(CraftServer.java:415) ~[patched_1.16.5.jar:git-Paper-629]
	at net.minecraft.server.v1_16_R3.MinecraftServer.loadWorld(MinecraftServer.java:591) ~[patched_1.16.5.jar:git-Paper-629]
	at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:281) ~[patched_1.16.5.jar:git-Paper-629]
	at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1065) ~[patched_1.16.5.jar:git-Paper-629]
	at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:289) ~[patched_1.16.5.jar:git-Paper-629]
	at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.lang.ClassNotFoundException: me.mrCookieSlime.Slimefun.Objects.SlimefunItem.UnregisterReason
	at java.net.URLClassLoader.findClass(URLClassLoader.java:471) ~[?:?]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:182) ~[patched_1.16.5.jar:git-Paper-629]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:111) ~[patched_1.16.5.jar:git-Paper-629]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:589) ~[?:?]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[?:?]
	... 12 more
[22:43:58] [Server thread/INFO]: [SoundMuffler] Disabling SoundMuffler vDEV - 20 (git cde78980)