On 1.8.9 can't join any 1.20 server.

[MarkGG8181]

Hi, so I have my own client and I have had ViaVersion for some time now but since they updated to 1.20 I still had 1.19.4, so I changed the jar files and re-downloaded all the source files & folders for viamcp 1.8.x and added them. I get these errors when I try to join any server with 1.20:

java.util.concurrent.ExecutionException: java.lang.NullPointerException
    at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_361]
    at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_361]
    at net.minecraft.util.Util.runTask(Util.java:20) [raze/:?]
    at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1025) [raze/:?]
    at net.minecraft.client.Minecraft.run(Minecraft.java:344) [raze/:?]
    at net.minecraft.client.main.Main.main(Main.java:113) [raze/:?]
    at Start.main(Start.java:11) [raze/:?]
Caused by: java.lang.NullPointerException
    at net.minecraft.client.network.NetHandlerPlayClient.handlePlayerPosLook(NetHandlerPlayClient.java:603) ~[raze/:?]
    at net.minecraft.network.play.server.S08PacketPlayerPosLook.processPacket(S08PacketPlayerPosLook.java:55) ~[raze/:?]
    at net.minecraft.network.play.server.S08PacketPlayerPosLook.processPacket(S08PacketPlayerPosLook.java:10) ~[raze/:?]
    at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:22) ~[raze/:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_361]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_361]
    at net.minecraft.util.Util.runTask(Util.java:19) ~[raze/:?]
    ... 4 more```

    Every other version works correctly with the version slider.

[ghost]

It seems that you have use newer ViaVersion. Right now ViaMCP is only support 1.20 preview or smt so it likely because of that.

[FlorianMichael]

Yeah, you can update ViaVersion by yourself, by just replacing the jar files and updating the ProtocolCollection enum class, but I am going to update ViaMCP soon TM

[FlorianMichael]

@FlorianMichael Also there are more client-side changes required to play newer versions. There are some packets missing, some other changes. Might want to add these.

ViaMCP won't get any official updates except the regular Via updates by me anymore, it's just to time consuming, I am doing the other direction (latest client -> 1.8 server) with my public mod "ViaFabricPlus".

[FlorianMichael]

Closing due to inactivity, if the issue still appears on your end try to update Via* libraries to latest and open a new issue, if you have any questions you can ask them here.