diff --git a/src/main/java/com/github/creeper123123321/viafabric/mixin/client/MixinCustomPayloadPacket.java b/src/main/java/com/github/creeper123123321/viafabric/mixin/client/MixinCustomPayloadPacket.java
new file mode 100644
index 0000000..ffb5825
--- /dev/null
+++ b/src/main/java/com/github/creeper123123321/viafabric/mixin/client/MixinCustomPayloadPacket.java
@@ -0,0 +1,96 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 creeper123123321 and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.github.creeper123123321.viafabric.mixin.client;
+
+import net.fabricmc.fabric.impl.network.PacketTypes;
+import net.minecraft.client.network.packet.CustomPayloadS2CPacket;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.InvalidIdentifierException;
+import net.minecraft.util.PacketByteBuf;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import us.myles.ViaVersion.api.Via;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.HashSet;
+import java.util.Set;
+
+@Mixin(CustomPayloadS2CPacket.class)
+public class MixinCustomPayloadPacket {
+
+	@Inject(method = "read", at = @At(value = "HEAD", target = "Lnet/minecraft/network/Packet;read(Lnet/minecraft/util/PacketByteBuf;)V"))
+	private void onRead(PacketByteBuf buf, CallbackInfo callbackInfo) throws IOException {
+		try {
+			int readerIndex = buf.readerIndex();
+
+			Identifier identifier = buf.readIdentifier();
+
+			buf.readerIndex(readerIndex);
+
+			if (identifier.equals(PacketTypes.REGISTER) || identifier.equals(PacketTypes.UNREGISTER)) {
+				Set<Identifier> identifiers = new HashSet();
+				StringBuilder builder = new StringBuilder();
+
+				while (buf.readerIndex() < buf.writerIndex()) {
+					char c = (char) buf.readByte();
+					if (c == 0 || buf.readableBytes() == 0) {
+						String s = builder.toString();
+						if (!s.isEmpty()) {
+							try {
+								identifiers.add(new Identifier(s));
+							} catch (InvalidIdentifierException ex) {
+								Via.getPlatform().getLogger().info("Ignoring invalid custom payload identifier in (un)register:\n" + ex.getMessage());
+							}
+						}
+
+						builder = new StringBuilder();
+					} else {
+						builder.append(c);
+					}
+				}
+
+				buf.clear();
+				buf.writeIdentifier(identifier);
+
+				boolean first = true;
+				for (Identifier id : identifiers) {
+					if (!first) {
+						buf.writeByte(0);
+					} else {
+						first = false;
+					}
+					buf.writeBytes(id.toString().getBytes(StandardCharsets.US_ASCII));
+				}
+			}
+		} catch (InvalidIdentifierException ex) {
+			Via.getPlatform().getLogger().warning("Ignoring invalid custom payload identifier:\n" + ex.getMessage());
+			buf.clear();
+			buf.writeString("viafabric:invalid");
+		}
+	}
+}
diff --git a/src/main/resources/mixins.viafabric.json b/src/main/resources/mixins.viafabric.json
index 6c13530..f4b9fed 100644
--- a/src/main/resources/mixins.viafabric.json
+++ b/src/main/resources/mixins.viafabric.json
@@ -8,7 +8,8 @@
   ],
   "client": [
     "client.MixinClientConnectionChInit",
-    "client.MixinMultiplayerScreen"
+    "client.MixinMultiplayerScreen",
+    "client.MixinCustomPayloadPacket"
   ],
   "injectors": {
     "defaultRequire": 1