--- a/net/minecraft/server/dedicated/DedicatedServerProperties.java
+++ b/net/minecraft/server/dedicated/DedicatedServerProperties.java
@@ -43,11 +43,16 @@
 import net.minecraft.world.level.levelgen.presets.WorldPresets;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import joptsimple.OptionSet;
+// CraftBukkit end
+
 public class DedicatedServerProperties extends Settings<DedicatedServerProperties> {
 
     static final Logger LOGGER = LogUtils.getLogger();
     private static final Pattern SHA1 = Pattern.compile("^[a-fA-F0-9]{40}$");
     private static final Splitter COMMA_SPLITTER = Splitter.on(',').trimResults();
+    public final boolean debug = this.get("debug", false); // CraftBukkit
     public final boolean onlineMode = this.get("online-mode", true);
     public final boolean preventProxyConnections = this.get("prevent-proxy-connections", false);
     public final String serverIp = this.get("server-ip", "");
@@ -100,13 +105,17 @@
     public final Settings<DedicatedServerProperties>.MutableValue<Boolean> whiteList;
     public final boolean enforceSecureProfile;
     public final boolean logIPs;
-    public final int pauseWhenEmptySeconds;
+    public int pauseWhenEmptySeconds;
     private final DedicatedServerProperties.WorldDimensionData worldDimensionData;
     public final WorldOptions worldOptions;
     public boolean acceptsTransfers;
 
-    public DedicatedServerProperties(Properties properties) {
-        super(properties);
+    public final String rconIp; // Paper - Configurable rcon ip
+
+    // CraftBukkit start
+    public DedicatedServerProperties(Properties properties, OptionSet optionset) {
+        super(properties, optionset);
+        // CraftBukkit end
         this.difficulty = (Difficulty) this.get("difficulty", dispatchNumberOrString(Difficulty::byId, Difficulty::byName), Difficulty::getKey, Difficulty.EASY);
         this.gamemode = (GameType) this.get("gamemode", dispatchNumberOrString(GameType::byId, GameType::byName), GameType::getName, GameType.SURVIVAL);
         this.levelName = this.get("level-name", "world");
@@ -137,7 +146,7 @@
         this.maxWorldSize = this.get("max-world-size", (integer) -> {
             return Mth.clamp(integer, 1, 29999984);
         }, 29999984);
-        this.syncChunkWrites = this.get("sync-chunk-writes", true);
+        this.syncChunkWrites = this.get("sync-chunk-writes", true) && Boolean.getBoolean("Paper.enable-sync-chunk-writes"); // Paper - Hide sync chunk writes behind flag
         this.regionFileComression = this.get("region-file-compression", "deflate");
         this.enableJmxMonitoring = this.get("enable-jmx-monitoring", false);
         this.enableStatus = this.get("enable-status", true);
@@ -165,15 +174,21 @@
         }, WorldPresets.NORMAL.location().toString()));
         this.serverResourcePackInfo = DedicatedServerProperties.getServerPackInfo(this.get("resource-pack-id", ""), this.get("resource-pack", ""), this.get("resource-pack-sha1", ""), this.getLegacyString("resource-pack-hash"), this.get("require-resource-pack", false), this.get("resource-pack-prompt", ""));
         this.initialDataPackConfiguration = DedicatedServerProperties.getDatapackConfig(this.get("initial-enabled-packs", String.join(",", WorldDataConfiguration.DEFAULT.dataPacks().getEnabled())), this.get("initial-disabled-packs", String.join(",", WorldDataConfiguration.DEFAULT.dataPacks().getDisabled())));
+        // Paper start - Configurable rcon ip
+        final String rconIp = this.getStringRaw("rcon.ip");
+        this.rconIp = rconIp == null ? this.serverIp : rconIp;
+        // Paper end - Configurable rcon ip
     }
 
-    public static DedicatedServerProperties fromFile(Path path) {
-        return new DedicatedServerProperties(loadFromFile(path));
+    // CraftBukkit start
+    public static DedicatedServerProperties fromFile(Path path, OptionSet optionset) {
+        return new DedicatedServerProperties(loadFromFile(path), optionset);
     }
 
     @Override
-    protected DedicatedServerProperties reload(RegistryAccess registryManager, Properties properties) {
-        return new DedicatedServerProperties(properties);
+    public DedicatedServerProperties reload(RegistryAccess iregistrycustom, Properties properties, OptionSet optionset) {
+        return new DedicatedServerProperties(properties, optionset);
+        // CraftBukkit end
     }
 
     @Nullable
@@ -254,10 +269,10 @@
             }).orElseThrow(() -> {
                 return new IllegalStateException("Invalid datapack contents: can't find default preset");
             });
-            Optional optional = Optional.ofNullable(ResourceLocation.tryParse(this.levelType)).map((minecraftkey) -> {
+            Optional<ResourceKey<WorldPreset>> optional = Optional.ofNullable(ResourceLocation.tryParse(this.levelType)).map((minecraftkey) -> { // CraftBukkit - decompile error
                 return ResourceKey.create(Registries.WORLD_PRESET, minecraftkey);
             }).or(() -> {
-                return Optional.ofNullable((ResourceKey) DedicatedServerProperties.WorldDimensionData.LEGACY_PRESET_NAMES.get(this.levelType));
+                return Optional.ofNullable(DedicatedServerProperties.WorldDimensionData.LEGACY_PRESET_NAMES.get(this.levelType)); // CraftBukkit - decompile error
             });
 
             Objects.requireNonNull(holderlookup);
@@ -269,7 +284,7 @@
 
             if (holder.is(WorldPresets.FLAT)) {
                 RegistryOps<JsonElement> registryops = registries.createSerializationContext(JsonOps.INSTANCE);
-                DataResult dataresult = FlatLevelGeneratorSettings.CODEC.parse(new Dynamic(registryops, this.generatorSettings()));
+                DataResult<FlatLevelGeneratorSettings> dataresult = FlatLevelGeneratorSettings.CODEC.parse(new Dynamic(registryops, this.generatorSettings())); // CraftBukkit - decompile error
                 Logger logger = DedicatedServerProperties.LOGGER;
 
                 Objects.requireNonNull(logger);