diff --git a/build.gradle b/build.gradle
index 8e2c395f..dbd4a66d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -89,6 +89,9 @@ dependencies {
 
     // compile against the JEI API but do not include it at runtime
     modCompileOnly("mezz.jei:jei-${minecraft_version}-forge:${jei_version}")
+    modRuntimeOnly("curse.maven:jei-238222:4352925")
+
+    modImplementation("curse.maven:jeresources-240630:3831559")
 }
 
 tasks.withType(JavaCompile) {
diff --git a/src/main/java/org/embeddedt/modernfix/ModernFix.java b/src/main/java/org/embeddedt/modernfix/ModernFix.java
index 6e0d7274..2af32f35 100644
--- a/src/main/java/org/embeddedt/modernfix/ModernFix.java
+++ b/src/main/java/org/embeddedt/modernfix/ModernFix.java
@@ -4,18 +4,20 @@ import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.event.server.ServerStartedEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.DistExecutor;
-import net.minecraftforge.fml.IExtensionPoint;
-import net.minecraftforge.fml.ModList;
-import net.minecraftforge.fml.ModLoadingContext;
+import net.minecraftforge.fml.*;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.fml.config.ModConfig;
+import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
+import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
 import net.minecraftforge.fml.loading.FMLLoader;
 import net.minecraftforge.network.NetworkConstants;
 import org.apache.commons.lang3.tuple.Pair;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.embeddedt.modernfix.core.config.ModernFixConfig;
+import org.embeddedt.modernfix.entity.EntityDataIDSyncHandler;
+import org.embeddedt.modernfix.packet.PacketHandler;
+
 
 import java.lang.management.ManagementFactory;
 import java.util.concurrent.CountDownLatch;
@@ -62,9 +64,30 @@ public class ModernFix {
         INSTANCE = this;
         // Register ourselves for server and other game events we are interested in
         MinecraftForge.EVENT_BUS.register(this);
+        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::commonSetup);
         DistExecutor.unsafeRunWhenOn(Dist.CLIENT, () -> () -> MinecraftForge.EVENT_BUS.register(new ModernFixClient()));
         ModLoadingContext.get().registerExtensionPoint(IExtensionPoint.DisplayTest.class, () -> new IExtensionPoint.DisplayTest(() -> NetworkConstants.IGNORESERVERONLY, (a, b) -> true));
         ModLoadingContext.get().registerConfig(ModConfig.Type.COMMON, ModernFixConfig.COMMON_CONFIG);
+
+        MinecraftForge.EVENT_BUS.register(EntityDataIDSyncHandler.class);
+        PacketHandler.register();
+    }
+
+    private static boolean dfuModPresent() {
+        for(String modId : new String[] { "lazydfu", "datafixerslayer" }) {
+            if(ModList.get().isLoaded(modId))
+                return true;
+        }
+        return false;
+    }
+
+    @SubscribeEvent
+    public void commonSetup(FMLCommonSetupEvent event) {
+        if(!dfuModPresent()) {
+            event.enqueueWork(() -> {
+                ModLoader.get().addWarning(new ModLoadingWarning(ModLoadingContext.get().getActiveContainer().getModInfo(), ModLoadingStage.COMMON_SETUP, "modernfix.no_lazydfu"));
+            });
+        }
     }
 
     @SubscribeEvent
diff --git a/src/main/java/org/embeddedt/modernfix/ModernFixClient.java b/src/main/java/org/embeddedt/modernfix/ModernFixClient.java
index a3175de9..ef61b7ae 100644
--- a/src/main/java/org/embeddedt/modernfix/ModernFixClient.java
+++ b/src/main/java/org/embeddedt/modernfix/ModernFixClient.java
@@ -1,9 +1,15 @@
 package org.embeddedt.modernfix;
 
+import com.mojang.datafixers.util.Pair;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screens.ConnectScreen;
 import net.minecraft.client.gui.screens.TitleScreen;
 import net.minecraftforge.client.event.ScreenOpenEvent;
+import net.minecraft.network.syncher.EntityDataAccessor;
+import net.minecraft.network.syncher.SynchedEntityData;
+import net.minecraft.world.entity.Entity;
 import net.minecraftforge.client.event.RenderGameOverlayEvent;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.event.TickEvent;
@@ -11,12 +17,17 @@ import net.minecraftforge.eventbus.api.EventPriority;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.ModContainer;
 import net.minecraftforge.fml.ModList;
+import net.minecraftforge.network.NetworkEvent;
 import org.embeddedt.modernfix.core.ModernFixMixinPlugin;
 import org.embeddedt.modernfix.load.LoadEvents;
+import org.embeddedt.modernfix.packet.EntityIDSyncPacket;
 import org.embeddedt.modernfix.screen.DeferredLevelLoadingScreen;
 
 import java.lang.management.ManagementFactory;
-import java.util.Optional;
+import java.lang.reflect.Field;
+import java.sql.Ref;
+import java.util.*;
+import java.util.function.Supplier;
 
 public class ModernFixClient {
     public static long worldLoadStartTime;
@@ -71,4 +82,78 @@ public class ModernFixClient {
             event.getLeft().add(brandingString);
         }
     }
+
+    /**
+     * Check if the IDs match and remap them if not.
+     * @return true if ID remap was needed
+     */
+    private static boolean compareAndSwitchIds(Class<? extends Entity> eClass, String fieldName, EntityDataAccessor<?> accessor, int newId) {
+        if(accessor.id != newId) {
+            ModernFix.LOGGER.warn("Corrected ID mismatch on {} field {}. Client had {} but server wants {}.",
+                    eClass,
+                    fieldName,
+                    accessor.id,
+                    newId);
+            accessor.id = newId;
+            return true;
+        } else {
+            ModernFix.LOGGER.debug("{} {} ID fine: {}", eClass, fieldName, newId);
+            return false;
+        }
+    }
+
+    /**
+     * Horrendous hack to allow tracking every synced entity data manager.
+     *
+     * This is to ensure we can perform ID fixup on already constructed managers.
+     */
+    public static Set<SynchedEntityData> allEntityDatas = Collections.newSetFromMap(new WeakHashMap<>());
+
+    /**
+     * Extremely hacky method to detect and correct mismatched entity data parameter IDs on the client and server.
+     *
+     * The technique is far from ideal, but it should detect reliably and also not break already constructed entities.
+     */
+    public static void handleEntityIDSync(EntityIDSyncPacket packet, Supplier<NetworkEvent.Context> context) {
+        Map<Class<? extends Entity>, List<Pair<String, Integer>>> info = packet.getFieldInfo();
+        context.get().enqueueWork(() -> {
+            boolean fixNeeded = false;
+            for(Map.Entry<Class<? extends Entity>, List<Pair<String, Integer>>> entry : info.entrySet()) {
+                Class<? extends Entity> eClass = entry.getKey();
+                for(Pair<String, Integer> field : entry.getValue()) {
+                    String fieldName = field.getFirst();
+                    int newId = field.getSecond();
+                    try {
+                        Field f = eClass.getDeclaredField(fieldName);
+                        f.setAccessible(true);
+                        EntityDataAccessor<?> accessor = (EntityDataAccessor<?>)f.get(null);
+                        if(compareAndSwitchIds(eClass, fieldName, accessor, newId))
+                            fixNeeded = true;
+                    } catch(NoSuchFieldException e) {
+                        ModernFix.LOGGER.warn("Couldn't find field on {}: {}", eClass, fieldName);
+                    } catch(ReflectiveOperationException e) {
+                        throw new RuntimeException("Unexpected exception", e);
+                    }
+                }
+            }
+            /* Now the ID mappings on synced entity data instances are probably all wrong. Fix that. */
+            List<SynchedEntityData> dataEntries;
+            synchronized (allEntityDatas) {
+                if(fixNeeded) {
+                    dataEntries = new ArrayList<>(allEntityDatas);
+                    for(SynchedEntityData manager : dataEntries) {
+                        Int2ObjectMap<SynchedEntityData.DataItem<?>> fixedMap = new Int2ObjectOpenHashMap<>();
+                        List<SynchedEntityData.DataItem<?>> items = new ArrayList<>(manager.itemsById.values());
+                        for(SynchedEntityData.DataItem<?> item : items) {
+                            fixedMap.put(item.getAccessor().id, item);
+                        }
+                        manager.itemsById = fixedMap;
+                    }
+                }
+                allEntityDatas.clear();
+            }
+        });
+
+        context.get().setPacketHandled(true);
+    }
 }
diff --git a/src/main/java/org/embeddedt/modernfix/blockstate/BlockStateCacheHandler.java b/src/main/java/org/embeddedt/modernfix/blockstate/BlockStateCacheHandler.java
index e9bd7c9f..4c439b5d 100644
--- a/src/main/java/org/embeddedt/modernfix/blockstate/BlockStateCacheHandler.java
+++ b/src/main/java/org/embeddedt/modernfix/blockstate/BlockStateCacheHandler.java
@@ -53,7 +53,7 @@ public class BlockStateCacheHandler {
                 currentRebuildThread = null;
             }
         } else {
-            ModernFix.LOGGER.warn("Deferred blockstate cache rebuild");
+            ModernFix.LOGGER.debug("Deferred blockstate cache rebuild");
         }
     }
 
diff --git a/src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java b/src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java
index 43ea82f2..1e525ee4 100644
--- a/src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java
+++ b/src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java
@@ -23,6 +23,7 @@ public class ModernFixEarlyConfig {
         this.addMixinRule("feature.measure_time", true);
         this.addMixinRule("feature.reduce_loading_screen_freezes", false);
         this.addMixinRule("perf.fast_registry_validation", true);
+        this.addMixinRule("perf.use_integrated_resources", true);
         this.addMixinRule("perf.remove_biome_temperature_cache", true);
         this.addMixinRule("perf.reduce_blockstate_cache_rebuilds", true);
         this.addMixinRule("perf.parallelize_model_loading", true);
@@ -31,6 +32,7 @@ public class ModernFixEarlyConfig {
         this.addMixinRule("perf.cache_upgraded_structures", true);
         this.addMixinRule("bugfix.concurrency", true);
         this.addMixinRule("bugfix.edge_chunk_not_saved", true);
+        this.addMixinRule("perf.async_jei", true);
         this.addMixinRule("perf.thread_priorities", true);
         this.addMixinRule("perf.sync_executor_sleep", true);
         this.addMixinRule("perf.scan_cache", true);
diff --git a/src/main/java/org/embeddedt/modernfix/duck/reuse_datapacks/ICachingResourceClient.java b/src/main/java/org/embeddedt/modernfix/duck/reuse_datapacks/ICachingResourceClient.java
new file mode 100644
index 00000000..030967d9
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/duck/reuse_datapacks/ICachingResourceClient.java
@@ -0,0 +1,10 @@
+package org.embeddedt.modernfix.duck.reuse_datapacks;
+
+import net.minecraft.server.ReloadableServerResources;
+
+import java.util.Collection;
+
+public interface ICachingResourceClient {
+    void setCachedResources(ReloadableServerResources r);
+    void setCachedDataPackConfig(Collection<String> c);
+}
diff --git a/src/main/java/org/embeddedt/modernfix/entity/EntityDataIDSyncHandler.java b/src/main/java/org/embeddedt/modernfix/entity/EntityDataIDSyncHandler.java
new file mode 100644
index 00000000..7be0a5ff
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/entity/EntityDataIDSyncHandler.java
@@ -0,0 +1,69 @@
+package org.embeddedt.modernfix.entity;
+
+import com.mojang.datafixers.util.Pair;
+import net.minecraft.network.syncher.EntityDataAccessor;
+import net.minecraft.network.syncher.SynchedEntityData;
+import net.minecraft.world.entity.Entity;
+import net.minecraftforge.event.OnDatapackSyncEvent;
+import net.minecraftforge.eventbus.api.EventPriority;
+import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.fml.util.ObfuscationReflectionHelper;
+import net.minecraftforge.network.PacketDistributor;
+import net.minecraftforge.server.ServerLifecycleHooks;
+import org.embeddedt.modernfix.ModernFix;
+import org.embeddedt.modernfix.packet.EntityIDSyncPacket;
+import org.embeddedt.modernfix.packet.PacketHandler;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class EntityDataIDSyncHandler {
+    private static Map<Class<? extends Entity>, List<Pair<String, Integer>>> fieldsToSyncMap;
+    @SubscribeEvent(priority = EventPriority.HIGHEST)
+    @SuppressWarnings("unchecked")
+    public static void onDatapackSyncEvent(OnDatapackSyncEvent event) {
+        if(event.getPlayer() != null) {
+            if(!ServerLifecycleHooks.getCurrentServer().isDedicatedServer() && event.getPlayerList().getPlayerCount() == 0) {
+                ModernFix.LOGGER.debug("Not syncing IDs on integrated server");
+                return;
+            }
+            /* Compute the current set of serializer IDs in use and send them */
+            try {
+                if(fieldsToSyncMap == null) {
+                    fieldsToSyncMap = new HashMap<>();
+                    Field entityPoolField = ObfuscationReflectionHelper.findField(SynchedEntityData.class, "f_135343_");
+                    Map<Class<? extends Entity>, Integer> entityPoolMap = (Map<Class<? extends Entity>, Integer>)entityPoolField.get(null);
+                    List<Field> fieldsToSync = new ArrayList<>();
+                    for(Class<? extends Entity> eClass : entityPoolMap.keySet()) {
+                        fieldsToSync.clear();
+                        Field[] classFields = eClass.getDeclaredFields();
+                        for(Field field : classFields) {
+                            if(!Modifier.isStatic(field.getModifiers()))
+                                continue;
+                            field.setAccessible(true);
+                            Object o = field.get(null);
+                            if(o != null && EntityDataAccessor.class.isAssignableFrom(o.getClass())) {
+                                fieldsToSync.add(field);
+                            }
+                        }
+                        for(Field field : fieldsToSync) {
+                            int id = ((EntityDataAccessor<?>)field.get(null)).id;
+                            fieldsToSyncMap.computeIfAbsent(eClass, k -> new ArrayList<>()).add(Pair.of(field.getName(), id));
+                        }
+                    }
+                }
+                EntityIDSyncPacket packet = new EntityIDSyncPacket(fieldsToSyncMap);
+                ModernFix.LOGGER.debug("Sending ID correction packet to client with " + fieldsToSyncMap.size() + " classes");
+                PacketHandler.INSTANCE.send(PacketDistributor.PLAYER.with(event::getPlayer), packet);
+            } catch(ObfuscationReflectionHelper.UnableToFindFieldException | ReflectiveOperationException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}
diff --git a/src/main/java/org/embeddedt/modernfix/mixin/core/SynchedEntityDataMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/core/SynchedEntityDataMixin.java
new file mode 100644
index 00000000..67133e3f
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/mixin/core/SynchedEntityDataMixin.java
@@ -0,0 +1,24 @@
+package org.embeddedt.modernfix.mixin.core;
+
+import net.minecraft.network.syncher.SynchedEntityData;
+import net.minecraft.world.entity.Entity;
+import org.embeddedt.modernfix.ModernFixClient;
+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;
+
+@Mixin(SynchedEntityData.class)
+public class SynchedEntityDataMixin {
+    /**
+     * Store this in our set of all entity data objects.
+     *
+     * Not an ideal solution, but it should guarantee compatibility with mods.
+     */
+    @Inject(method = "<init>", at = @At("RETURN"))
+    private void storeInSet(Entity arg, CallbackInfo ci) {
+        synchronized (ModernFixClient.allEntityDatas) {
+            ModernFixClient.allEntityDatas.add((SynchedEntityData)(Object)this);
+        }
+    }
+}
diff --git a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
index c0ca392e..9cd8f89f 100644
--- a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
+++ b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
@@ -9,6 +9,7 @@ import net.minecraft.server.packs.VanillaPackResources;
 import net.minecraft.server.packs.metadata.pack.PackMetadataSection;
 import org.apache.commons.lang3.tuple.Pair;
 import org.embeddedt.modernfix.FileWalker;
+import org.embeddedt.modernfix.util.FileUtil;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Overwrite;
@@ -71,7 +72,7 @@ public class VanillaPackResourcesMixin {
 
     @Inject(method = "hasResource", at = @At(value = "INVOKE", target = "Ljava/lang/Class;getResource(Ljava/lang/String;)Ljava/net/URL;"), cancellable = true)
     private void useCacheForExistence(PackType type, ResourceLocation location, CallbackInfoReturnable<Boolean> cir) {
-        cir.setReturnValue(containedPaths.contains(type.getDirectory() + "/" + location.getNamespace() + "/" + location.getPath()));
+        cir.setReturnValue(containedPaths.contains(type.getDirectory() + "/" + location.getNamespace() + "/" + FileUtil.normalize(location.getPath())));
     }
 
     /**
diff --git a/src/main/java/org/embeddedt/modernfix/mixin/perf/thread_priorities/IntegratedServerMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/perf/thread_priorities/IntegratedServerMixin.java
index 4f940e86..6f51f0b8 100644
--- a/src/main/java/org/embeddedt/modernfix/mixin/perf/thread_priorities/IntegratedServerMixin.java
+++ b/src/main/java/org/embeddedt/modernfix/mixin/perf/thread_priorities/IntegratedServerMixin.java
@@ -23,7 +23,6 @@ public class IntegratedServerMixin {
     @Inject(method = "<init>", at = @At("RETURN"))
     private void adjustServerPriority(Thread thread, Minecraft arg, LevelStorageSource.LevelStorageAccess arg2, PackRepository arg3, WorldStem arg4, MinecraftSessionService minecraftSessionService, GameProfileRepository gameProfileRepository, GameProfileCache arg5, ChunkProgressListenerFactory arg6, CallbackInfo ci) {
         int pri = ModernFixConfig.INTEGRATED_SERVER_PRIORITY.get();
-        ModernFix.LOGGER.info("Changing server thread priority to " + pri);
         thread.setPriority(pri);
     }
 }
diff --git a/src/main/java/org/embeddedt/modernfix/mixin/perf/use_integrated_resources/LootTableHelperMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/perf/use_integrated_resources/LootTableHelperMixin.java
new file mode 100644
index 00000000..8ec63f73
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/mixin/perf/use_integrated_resources/LootTableHelperMixin.java
@@ -0,0 +1,20 @@
+package org.embeddedt.modernfix.mixin.perf.use_integrated_resources;
+
+import jeresources.util.LootTableHelper;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.level.Level;
+import net.minecraftforge.server.ServerLifecycleHooks;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(LootTableHelper.class)
+public class LootTableHelperMixin {
+    @Redirect(method = "getLootTables", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/Level;getServer()Lnet/minecraft/server/MinecraftServer;"))
+    private static MinecraftServer useIntegrated(Level level) {
+        MinecraftServer server = level.getServer();
+        if(server != null)
+            return server;
+        return ServerLifecycleHooks.getCurrentServer();
+    }
+}
diff --git a/src/main/java/org/embeddedt/modernfix/packet/EntityIDSyncPacket.java b/src/main/java/org/embeddedt/modernfix/packet/EntityIDSyncPacket.java
new file mode 100644
index 00000000..6fe2c6b1
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/packet/EntityIDSyncPacket.java
@@ -0,0 +1,78 @@
+package org.embeddedt.modernfix.packet;
+
+import com.mojang.datafixers.util.Pair;
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.network.syncher.EntityDataAccessor;
+import net.minecraft.world.entity.Entity;
+import org.embeddedt.modernfix.ModernFix;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.*;
+
+public class EntityIDSyncPacket {
+    private Map<Class<? extends Entity>, List<Pair<String, Integer>>> map;
+
+    public EntityIDSyncPacket(Map<Class<? extends Entity>, List<Pair<String, Integer>>> map) {
+        this.map = map;
+    }
+
+    public Map<Class<? extends Entity>, List<Pair<String, Integer>>> getFieldInfo() {
+        return this.map;
+    }
+
+    public EntityIDSyncPacket() {
+        this.map = new HashMap<>();
+    }
+
+    public void serialize(FriendlyByteBuf buf) {
+        buf.writeVarInt(map.keySet().size());
+        for(Map.Entry<Class<? extends Entity>, List<Pair<String, Integer>>> entry : map.entrySet()) {
+            buf.writeUtf(entry.getKey().getName());
+            buf.writeVarInt(entry.getValue().size());
+            for(Pair<String, Integer> field : entry.getValue()) {
+                buf.writeUtf(field.getFirst());
+                buf.writeVarInt(field.getSecond());
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public static EntityIDSyncPacket deserialize(FriendlyByteBuf buf) {
+        EntityIDSyncPacket self = new EntityIDSyncPacket();
+        int numEntityClasses = buf.readVarInt();
+        for(int i = 0; i < numEntityClasses; i++) {
+            String clzName = buf.readUtf();
+            try {
+                Class<?> clz;
+                try {
+                    clz = Class.forName(clzName);
+                } catch(ClassNotFoundException e) {
+                    ModernFix.LOGGER.warn("Entity class not found: {}", clzName);
+                    break;
+                }
+                if(!Entity.class.isAssignableFrom(clz)) {
+                    ModernFix.LOGGER.error("Not an entity: " + clzName);
+                    break;
+                }
+                int numFields = buf.readVarInt();
+                for(int j = 0; j < numFields; j++) {
+                    String fieldName = buf.readUtf();
+                    int id = buf.readVarInt();
+                    Field f = clz.getDeclaredField(fieldName);
+                    if(!Modifier.isStatic(f.getModifiers()))
+                        continue;
+                    f.setAccessible(true);
+                    if(!EntityDataAccessor.class.isAssignableFrom(f.get(null).getClass())) {
+                        ModernFix.LOGGER.error("Not a data accessor field: " + clz + "." + fieldName);
+                        continue;
+                    }
+                    self.map.computeIfAbsent((Class<? extends Entity>)clz, k -> new ArrayList<>()).add(Pair.of(fieldName, id));
+                }
+            } catch(ReflectiveOperationException e) {
+                ModernFix.LOGGER.error("Error deserializing packet", e);
+            }
+        }
+        return self;
+    }
+}
diff --git a/src/main/java/org/embeddedt/modernfix/packet/PacketHandler.java b/src/main/java/org/embeddedt/modernfix/packet/PacketHandler.java
new file mode 100644
index 00000000..e489fea0
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/packet/PacketHandler.java
@@ -0,0 +1,22 @@
+package org.embeddedt.modernfix.packet;
+
+import net.minecraft.resources.ResourceLocation;
+import net.minecraftforge.network.NetworkRegistry;
+import net.minecraftforge.network.simple.SimpleChannel;
+import org.embeddedt.modernfix.ModernFix;
+import org.embeddedt.modernfix.ModernFixClient;
+
+public class PacketHandler {
+    private static final String PROTOCOL_VERSION = "1";
+    public static final SimpleChannel INSTANCE = NetworkRegistry.newSimpleChannel(
+            new ResourceLocation(ModernFix.MODID, "main"),
+            () -> PROTOCOL_VERSION,
+            NetworkRegistry.acceptMissingOr(PROTOCOL_VERSION),
+            NetworkRegistry.acceptMissingOr(PROTOCOL_VERSION)
+    );
+
+    public static void register() {
+        int id = 1;
+        INSTANCE.registerMessage(id++, EntityIDSyncPacket.class, EntityIDSyncPacket::serialize, EntityIDSyncPacket::deserialize, ModernFixClient::handleEntityIDSync);
+    }
+}
diff --git a/src/main/java/org/embeddedt/modernfix/util/FileUtil.java b/src/main/java/org/embeddedt/modernfix/util/FileUtil.java
index 7e8dda59..51045bda 100644
--- a/src/main/java/org/embeddedt/modernfix/util/FileUtil.java
+++ b/src/main/java/org/embeddedt/modernfix/util/FileUtil.java
@@ -1,10 +1,22 @@
 package org.embeddedt.modernfix.util;
 
 import java.io.File;
+import java.util.regex.Pattern;
 
 public class FileUtil {
     public static File childFile(File file) {
         file.getParentFile().mkdirs();
         return file;
     }
+
+    private static final Pattern SLASH_PATTERN = Pattern.compile("(?:\\\\+|\\/+)");
+
+    /**
+     * Normalize a path by removing double slashes, etc.
+     * @param path input path
+     * @return a normalized version of the path
+     */
+    public static String normalize(String path) {
+        return SLASH_PATTERN.matcher(path).replaceAll("/");
+    }
 }
diff --git a/src/main/resources/META-INF/accesstransformer.cfg b/src/main/resources/META-INF/accesstransformer.cfg
index 84ad721f..a366f6f0 100644
--- a/src/main/resources/META-INF/accesstransformer.cfg
+++ b/src/main/resources/META-INF/accesstransformer.cfg
@@ -8,4 +8,6 @@ public net.minecraft.client.renderer.model.ModelBakery field_217849_F # unbakedC
 public net.minecraft.client.renderer.texture.Stitcher$Holder
 public net.minecraft.util.thread.BlockableEventLoop m_18699_()V # runAllTasks
 public net.minecraft.server.MinecraftServer f_129726_ # nextTickTime
-public net.minecraft.client.Minecraft f_90999_ # progressListener
\ No newline at end of file
+public net.minecraft.client.Minecraft f_90999_ # progressListener
+public-f net.minecraft.network.syncher.EntityDataAccessor f_135010_ # id
+public-f net.minecraft.network.syncher.SynchedEntityData f_135345_ # itemsById
diff --git a/src/main/resources/assets/modernfix/lang/en_us.json b/src/main/resources/assets/modernfix/lang/en_us.json
index 8b1b7ad4..b757242b 100644
--- a/src/main/resources/assets/modernfix/lang/en_us.json
+++ b/src/main/resources/assets/modernfix/lang/en_us.json
@@ -1,5 +1,6 @@
 {
   "modernfix.jei_load": "Loading JEI, this may take a while",
+  "modernfix.no_lazydfu": "ModernFix detected that DFU rules were compiled on startup. This slows down game launching. Installing LazyDFU to resolve this is highly recommended.",
   "asynclocator.map.locating": "Map (Locating...)",
   "asynclocator.map.none": "Map (No nearby feature found)"
 }
diff --git a/src/main/resources/assets/modernfix/lang/zh_cn.json b/src/main/resources/assets/modernfix/lang/zh_cn.json
index 0c9c92a5..f8e78167 100644
--- a/src/main/resources/assets/modernfix/lang/zh_cn.json
+++ b/src/main/resources/assets/modernfix/lang/zh_cn.json
@@ -1,5 +1,6 @@
 {
-  "modernfix.jei_load": "正在加载JEI，这需要一点时间",
-  "asynclocator.map.locating": "地图（正在定位...）",
+  "modernfix.jei_load": "正在加载JEI，这需要一点时间。",
+  "modernfix.no_lazydfu": "现代化修复检测到DFU规则在游戏启动时已被编译。这会降低游戏启动速度。非常推荐安装DFU载入优化来解决这个问题。",
+  "asynclocator.map.locating": "地图（定位中……）",
   "asynclocator.map.none": "地图（未能找到相关地物）"
 }
diff --git a/src/main/resources/modernfix.mixins.json b/src/main/resources/modernfix.mixins.json
index baf3a38f..41647d5c 100644
--- a/src/main/resources/modernfix.mixins.json
+++ b/src/main/resources/modernfix.mixins.json
@@ -33,6 +33,7 @@
   ],
   "client": [
     "core.MinecraftMixin",
+    "core.SynchedEntityDataMixin",
     "feature.measure_time.MinecraftMixin",
     "feature.reduce_loading_screen_freezes.ModelBakeryMixin",
     "bugfix.concurrency.MinecraftMixin",
@@ -57,6 +58,7 @@
     "perf.cache_model_materials.VanillaModelMixin",
     "perf.cache_model_materials.MultipartMixin",
     "perf.faster_texture_stitching.StitcherMixin",
+    "perf.use_integrated_resources.LootTableHelperMixin",
     "perf.faster_singleplayer_load.MinecraftServerMixin"
   ],
   "injectors": {