The mod will attempt to automatically fix the error "Unknown serializer type 110" or other similar errors. The mod must be installed on client + server.

The root cause of these errors is that the server and client have ID numbers associated with specific "serializers" and if there is a mismatch of these numbers on the client/server, it will give an error "unknown serializer type".

After installing the mod, you should be able to successfully connect to the server.

This was developed primarily to fix a Cobblemon bug, but it should work for any mods that have a serializer de-sync issue.

The mod will by default log the serializer ID/object pair on the client and server, and if there is any de-sync, you will most likely be able to identify what the problem is based on the logs.

It will also attempt to auto-correct this error on the client side.

The mod has a config with the following options:

"Ignore serializer error":

Defaulted to FALSE - if toggled to true this option will forcefully ignore serializer errors, and as such it would be impossible to get the "unknown serializer type" error. It is not recommended to turn this on unless all else fails.

"Only Show Errors":

Defaulted to TRUE - If toggled to false it will do verbose printing of any entity ID serialization that happens. If set to true, it will only print when there is an error detected.

"Reorder client IDs":

Defaulted to TRUE - This is the setting that tries to automatically fix the de-sync on the client side. The server will send its serializer list to the client upon login, and the client will reorder its own internal serializer list to match that of the server. If the packet arrives, the client-side logs will show the log statement: "Handle ClientboundSerializerSyncPacket". If this packet has a mismatch with the client-side, it will reorder the client-side serializers. This will be logged as "Init remap:" - if you see this statement in the logs then you know that there was a de-sync and the client has been auto-corrected to match the server.

Below is an example of actual log output to fix Cobblemon, which frequently gets this error:

[27Dec2024 14:26:17.924] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remapping process using server data, size=51
[27Dec2024 14:26:17.925] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remap: from clientId=29 to serverId=28 for server className=com.cobblemon.mod.common.api.net.serializers.Vec3DataSerializer
[27Dec2024 14:26:17.925] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remap: from clientId=30 to serverId=29 for server className=com.cobblemon.mod.common.api.net.serializers.StringSetDataSerializer
[27Dec2024 14:26:17.926] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remap: from clientId=31 to serverId=30 for server className=com.cobblemon.mod.common.api.net.serializers.PoseTypeDataSerializer
[27Dec2024 14:26:17.926] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remap: from clientId=32 to serverId=31 for server className=com.cobblemon.mod.common.api.net.serializers.IdentifierDataSerializer
[27Dec2024 14:26:17.926] [Netty Client IO #10/ERROR] [net.minecraft.network.syncher.EntityDataSerializers/]: [SerializerDebug] Init remap: from clientId=28 to serverId=32 for server className=com.bobmowzie.mowziesmobs.server.ServerProxy$1