Index: src/main/java/net/minecraft/server/DataConverterRegistry.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/main/java/net/minecraft/server/DataConverterRegistry.java b/src/main/java/net/minecraft/server/DataConverterRegistry.java
--- a/src/main/java/net/minecraft/server/DataConverterRegistry.java	(revision ec1b4311cebfd9bc35a5f84f56df46cf7319649a)
+++ b/src/main/java/net/minecraft/server/DataConverterRegistry.java	(date 1609015897972)
@@ -1,26 +1,63 @@
 package net.minecraft.server;
 
 import com.google.common.collect.ImmutableMap;
-import com.mojang.datafixers.DSL;
-import com.mojang.datafixers.DataFixer;
-import com.mojang.datafixers.DataFixerBuilder;
-import com.mojang.datafixers.Typed;
+import com.google.common.collect.Maps;
+import com.mojang.datafixers.*;
 import com.mojang.datafixers.schemas.Schema;
+import com.mojang.datafixers.types.DynamicOps;
+import com.mojang.datafixers.types.Type;
+import com.mojang.datafixers.types.templates.TypeTemplate;
+import com.mojang.datafixers.util.Pair;
+
+import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.BiFunction;
+import java.util.function.Supplier;
 
 public class DataConverterRegistry {
 
     private static final BiFunction<Integer, Schema, Schema> a = Schema::new;
     private static final BiFunction<Integer, Schema, Schema> b = DataConverterSchemaNamed::new;
-    private static final DataFixer c = b();
+    private static final DataFixer c = new DataFixer() {
+        @Override
+        public <T> Dynamic<T> update(DSL.TypeReference typeReference, Dynamic<T> dynamic, int i, int i1) {
+            return dynamic;
+        }
+
+        @Override
+        public Schema getSchema(int i) {
+            return new Schema(i, null){
+                @Override
+                public void registerTypes(Schema schema, Map<String, Supplier<TypeTemplate>> entityTypes, Map<String, Supplier<TypeTemplate>> blockEntityTypes) {}
+
+                @Override
+                public Map<String, Supplier<TypeTemplate>> registerEntities(Schema schema) {
+                    return Maps.newHashMap();
+                }
+
+                @Override
+                public Map<String, Supplier<TypeTemplate>> registerBlockEntities(Schema schema) {
+                    return Maps.newHashMap();
+                }
 
-    private static DataFixer b() {
-        DataFixerBuilder datafixerbuilder = new DataFixerBuilder(SharedConstants.getGameVersion().getWorldVersion());
+                @Override
+                protected Map<String, Type<?>> buildTypes() {
+                    return Maps.newHashMap();
+                }
 
-        a(datafixerbuilder);
-        return datafixerbuilder.build(SystemUtils.e());
-    }
+                @Override
+                public Type<?> getType(DSL.TypeReference type) {
+                    return null;
+                }
+
+                @Override
+                public Type<?> getChoiceType(DSL.TypeReference type, String choiceName) {
+                    return null;
+                }
+            };
+        }
+    };
 
     public static DataFixer a() {
         return DataConverterRegistry.c;