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1.21.8 server, 1.21.9 client gets kicked when joins (ViaVersion)

Is there some way you can fix this? I'm not even using PacketEvents on the server (I assume it injects or loads it, or potentially through GrimAC). It causes issues not being joinable from 1.21.9. My other servers are working, which leads me to believe it's a MythicLib issue.
Using latest MythicLib & MMOItems on 1.21.8 (client is joining on 1.21.9 through ViaVersion)
[15:07:24] [Netty Epoll Server IO #0/WARN]: [ac.grim.grimac.shaded.com.github.retrooper.packetevents.PacketEventsAPI] An error occurred while processing a packet from jonaas13 (state: PLAY, clientVersion: 1.21.7, serverVersion: 1.21.8, preVia: true)
ac.grim.grimac.shaded.com.github.retrooper.packetevents.exception.PacketProcessException: Failed to map the Packet ID 136 to a PacketType constant. Bound: CLIENT, Connection state: PLAY, Server version: 1.21.7
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.com.github.retrooper.packetevents.event.ProtocolPacketEvent.<init>(ProtocolPacketEvent.java:92) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.com.github.retrooper.packetevents.event.PacketSendEvent.<init>(PacketSendEvent.java:37) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.com.github.retrooper.packetevents.event.simple.PacketPlaySendEvent.<init>(PacketPlaySendEvent.java:33) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.com.github.retrooper.packetevents.util.EventCreationUtil.createSendEvent(EventCreationUtil.java:55) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.com.github.retrooper.packetevents.util.PacketEventsImplHelper.handleClientBoundPacket(PacketEventsImplHelper.java:59) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.io.github.retrooper.packetevents.injector.handlers.PacketEventsEncoder.handleClientBoundPacket(PacketEventsEncoder.java:87) ~[grimac-bukkit-2.3.72.jar:?]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.io.github.retrooper.packetevents.injector.handlers.PacketEventsEncoder.write(PacketEventsEncoder.java:113) ~[grimac-bukkit-2.3.72.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:113) ~[netty-codec-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at grimac-bukkit-2.3.72.jar/ac.grim.grimac.shaded.io.github.retrooper.packetevents.injector.handlers.PacketEventsEncoder.write(PacketEventsEncoder.java:131) ~[grimac-bukkit-2.3.72.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at packetevents-spigot-2.9.5.jar/io.github.retrooper.packetevents.injector.handlers.PacketEventsEncoder.write(PacketEventsEncoder.java:122) ~[packetevents-spigot-2.9.5.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:113) ~[netty-codec-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:113) ~[netty-codec-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:120) ~[netty-codec-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.ChannelOutboundHandlerAdapter.write(ChannelOutboundHandlerAdapter.java:113) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at net.minecraft.network.Connection$2.write(Connection.java:729) ~[purpur-1.21.8.jar:1.21.8-2497-a49cdb9]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at oraxen-1.193.3.jar/io.th0rgal.oraxen.nms.v1_21_R5.NMSHandler$1.write(NMSHandler.java:106) ~[oraxen-1.193.3.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:891) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.ChannelDuplexHandler.write(ChannelDuplexHandler.java:115) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at MythicLib-dist-1.7.1-20250916.170846-40.jar/io.lumine.mythic.lib.util.network.LightInjector$PacketHandler.write(LightInjector.java:509) ~[MythicLib-dist-1.7.1-20250916.170846-40.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:891) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:875) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:877) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:877) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:877) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:877) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:868) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:120) ~[netty-codec-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:893) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:956) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:982) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:950) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:969) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:310) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
	at ProtocolLib.jar/com.comphenix.protocol.injector.netty.channel.NettyChannelProxy.writeAndFlush(NettyChannelProxy.java:227) ~[ProtocolLib.jar:?]
	at net.minecraft.network.Connection.doSendPacket(Connection.java:495) ~[purpur-1.21.8.jar:1.21.8-2497-a49cdb9]
	at net.minecraft.network.Connection.lambda$sendPacket$13(Connection.java:477) ~[purpur-1.21.8.jar:1.21.8-2497-a49cdb9]
	at ProtocolLib.jar/com.comphenix.protocol.injector.netty.channel.NettyEventLoopProxy.lambda$proxyRunnable$2(NettyEventLoopProxy.java:49) ~[ProtocolLib.jar:?]
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173) ~[netty-common-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166) ~[netty-common-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) ~[netty-common-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:405) ~[netty-transport-classes-epoll-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:998) ~[netty-common-4.1.118.Final.jar:4.1.118.Final]
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.118.Final.jar:4.1.118.Final]
	at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
[15:07:24] [Netty Epoll Server IO #0/INFO]: [packetevents] Disconnected jonaas13 due to an invalid packet!
Edited Oct 03, 2025 by jonaas13