diff --git a/.gitmodules b/.gitmodules
index df60ddab7..8dc22a2d7 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,10 +1,3 @@
-[submodule "src/raklib"]
-	path = src/raklib
-	url = https://github.com/pmmp/RakLib.git
-	branch = master
-[submodule "src/spl"]
-	path = src/spl
-	url = https://github.com/pmmp/PocketMine-SPL.git
 [submodule "src/pocketmine/lang/locale"]
 	path = src/pocketmine/lang/locale
 	url = https://github.com/pmmp/PocketMine-Language.git
diff --git a/composer.json b/composer.json
index 3c5b01883..1087d4eff 100644
--- a/composer.json
+++ b/composer.json
@@ -5,7 +5,7 @@
    "homepage": "https://pmmp.io",
    "license": "LGPL-3.0",
    "require": {
-      "php": ">=7.2",
+      "php": ">=7.2.0RC3",
       "ext-bcmath": "*",
       "ext-curl": "*",
       "ext-hash": "*",
@@ -20,14 +20,23 @@
       "ext-spl": "*",
       "ext-yaml": ">=2.0.0",
       "ext-zip": "*",
-      "ext-zlib": ">=1.2.11"
+      "ext-zlib": ">=1.2.11",
+      "pmmp/raklib": "^0.9.0",
+      "pmmp/pocketmine-spl": "^0.0.2"
    },
    "autoload": {
-      "exclude-from-classmap": [
-        "src/spl/stubs"
-      ],
       "psr-0": {
-         "": ["src", "src/spl"]
+         "": ["src"]
       }
-   }
+   },
+   "repositories": [
+      {
+         "type": "vcs",
+         "url": "https://github.com/pmmp/RakLib"
+      },
+      {
+         "type": "vcs",
+         "url": "https://github.com/pmmp/PocketMine-SPL"
+      }
+   ]
 }
diff --git a/composer.lock b/composer.lock
index f23e45dd8..22090967c 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,18 +4,89 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "d4fecad9dce5314493052c870c8cf059",
-    "packages": [],
+    "content-hash": "55bdbaf13ac4ea71f0705f03f715172d",
+    "packages": [
+        {
+            "name": "pmmp/pocketmine-spl",
+            "version": "0.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/pmmp/PocketMine-SPL.git",
+                "reference": "065b631d63e2c4ddb3141f63a07a9ecbab8357d1"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/pmmp/PocketMine-SPL/zipball/065b631d63e2c4ddb3141f63a07a9ecbab8357d1",
+                "reference": "065b631d63e2c4ddb3141f63a07a9ecbab8357d1",
+                "shasum": ""
+            },
+            "type": "library",
+            "autoload": {
+                "exclude-from-classmap": [
+                    "stubs"
+                ],
+                "classmap": [
+                    "./"
+                ]
+            },
+            "license": [
+                "LGPL-3.0"
+            ],
+            "description": "Standard library files required by PocketMine-MP and related projects",
+            "support": {
+                "source": "https://github.com/pmmp/PocketMine-SPL/tree/0.0.2"
+            },
+            "time": "2017-11-14T18:56:38+00:00"
+        },
+        {
+            "name": "pmmp/raklib",
+            "version": "0.9.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/pmmp/RakLib.git",
+                "reference": "08470471eb16b4325fa02415fd12c5060eba9c34"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/pmmp/RakLib/zipball/08470471eb16b4325fa02415fd12c5060eba9c34",
+                "reference": "08470471eb16b4325fa02415fd12c5060eba9c34",
+                "shasum": ""
+            },
+            "require": {
+                "ext-bcmath": "*",
+                "ext-pthreads": ">=3.1.7dev",
+                "ext-sockets": "*",
+                "php": ">=7.2.0RC3",
+                "pmmp/pocketmine-spl": "^0.0.2"
+            },
+            "type": "library",
+            "autoload": {
+                "classmap": [
+                    "./"
+                ]
+            },
+            "license": [
+                "GPL-3.0"
+            ],
+            "description": "A RakNet server implementation written in PHP",
+            "support": {
+                "source": "https://github.com/pmmp/RakLib/tree/0.9.0",
+                "issues": "https://github.com/pmmp/RakLib/issues"
+            },
+            "time": "2017-11-14T19:03:14+00:00"
+        }
+    ],
     "packages-dev": [],
     "aliases": [],
     "minimum-stability": "stable",
     "stability-flags": {
+        "php": 5,
         "ext-pthreads": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": ">=7.2",
+        "php": ">=7.2.0RC3",
         "ext-bcmath": "*",
         "ext-curl": "*",
         "ext-hash": "*",
diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index 1375040a9..17f6ace46 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -97,9 +97,7 @@ use pocketmine\metadata\MetadataValue;
 use pocketmine\nbt\NBT;
 use pocketmine\nbt\tag\ByteTag;
 use pocketmine\nbt\tag\CompoundTag;
-use pocketmine\nbt\tag\IntTag;
-use pocketmine\nbt\tag\LongTag;
-use pocketmine\nbt\tag\StringTag;
+use pocketmine\nbt\tag\ListTag;
 use pocketmine\network\mcpe\PlayerNetworkSessionAdapter;
 use pocketmine\network\mcpe\protocol\AdventureSettingsPacket;
 use pocketmine\network\mcpe\protocol\AnimatePacket;
@@ -1331,7 +1329,7 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 
 		$this->resetFallDistance();
 
-		$this->namedtag->playerGameType = new IntTag("playerGameType", $this->gamemode);
+		$this->namedtag->setInt("playerGameType", $this->gamemode);
 		if(!$client){ //Gamemode changed by server, do not send for client changes
 			$this->sendGamemode();
 		}else{
@@ -1893,15 +1891,12 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 		$this->namedtag = $this->server->getOfflinePlayerData($this->username);
 
 		$this->playedBefore = ($this->namedtag["lastPlayed"] - $this->namedtag["firstPlayed"]) > 1; // microtime(true) - microtime(true) may have less than one millisecond difference
-		if(!isset($this->namedtag->NameTag)){
-			$this->namedtag->NameTag = new StringTag("NameTag", $this->username);
-		}else{
-			$this->namedtag["NameTag"] = $this->username;
-		}
-		$this->gamemode = $this->namedtag["playerGameType"] & 0x03;
+		$this->namedtag->setString("NameTag", $this->username);
+
+		$this->gamemode = $this->namedtag->getInt("playerGameType", self::SURVIVAL) & 0x03;
 		if($this->server->getForceGamemode()){
 			$this->gamemode = $this->server->getGamemode();
-			$this->namedtag->playerGameType = new IntTag("playerGameType", $this->gamemode);
+			$this->namedtag->setInt("playerGameType", $this->gamemode);
 		}
 
 		$this->allowFlight = $this->isCreative();
@@ -1918,12 +1913,13 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 
 		$this->achievements = [];
 
+		$achievements = $this->namedtag->getCompoundTag("Achievements") ?? [];
 		/** @var ByteTag $achievement */
-		foreach($this->namedtag->Achievements as $achievement){
+		foreach($achievements as $achievement){
 			$this->achievements[$achievement->getName()] = $achievement->getValue() !== 0;
 		}
 
-		$this->namedtag->lastPlayed = new LongTag("lastPlayed", (int) floor(microtime(true) * 1000));
+		$this->namedtag->setLong("lastPlayed", (int) floor(microtime(true) * 1000));
 		if($this->server->getAutoSave()){
 			$this->server->saveOfflinePlayerData($this->username, $this->namedtag, true);
 		}
@@ -1950,8 +1946,8 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 		}
 
 		if(!$this->hasValidSpawnPosition()){
-			if(isset($this->namedtag->SpawnLevel) and ($level = $this->server->getLevelByName((string) $this->namedtag["SpawnLevel"])) instanceof Level){
-				$this->spawnPosition = new WeakPosition($this->namedtag["SpawnX"], $this->namedtag["SpawnY"], $this->namedtag["SpawnZ"], $level);
+			if(($level = $this->server->getLevelByName($this->namedtag->getString("SpawnLevel", ""))) instanceof Level){
+				$this->spawnPosition = new WeakPosition($this->namedtag->getInt("SpawnX"), $this->namedtag->getInt("SpawnY"), $this->namedtag->getInt("SpawnZ"), $level);
 			}else{
 				$this->spawnPosition = WeakPosition::fromObject($this->level->getSafeSpawn());
 			}
@@ -3499,22 +3495,24 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 		parent::saveNBT();
 
 		if($this->isValid()){
-			$this->namedtag->Level = new StringTag("Level", $this->level->getFolderName());
+			$this->namedtag->setString("Level", $this->level->getFolderName());
 		}
 
 		if($this->hasValidSpawnPosition()){
-			$this->namedtag->SpawnLevel = new StringTag("SpawnLevel", $this->spawnPosition->getLevel()->getFolderName());
-			$this->namedtag->SpawnX = new IntTag("SpawnX", (int) $this->spawnPosition->x);
-			$this->namedtag->SpawnY = new IntTag("SpawnY", (int) $this->spawnPosition->y);
-			$this->namedtag->SpawnZ = new IntTag("SpawnZ", (int) $this->spawnPosition->z);
+			$this->namedtag->setString("SpawnLevel", $this->spawnPosition->getLevel()->getFolderName());
+			$this->namedtag->setInt("SpawnX", (int) $this->spawnPosition->x);
+			$this->namedtag->setInt("SpawnY", (int) $this->spawnPosition->y);
+			$this->namedtag->setInt("SpawnZ", (int) $this->spawnPosition->z);
 		}
 
+		$achievements = new CompoundTag("Achievements");
 		foreach($this->achievements as $achievement => $status){
-			$this->namedtag->Achievements[$achievement] = new ByteTag($achievement, $status === true ? 1 : 0);
+			$achievements->setByte($achievement, $status === true ? 1 : 0);
 		}
+		$this->namedtag->setTag($achievements);
 
-		$this->namedtag["playerGameType"] = $this->gamemode;
-		$this->namedtag["lastPlayed"] = (int) floor(microtime(true) * 1000);
+		$this->namedtag->setInt("playerGameType", $this->gamemode);
+		$this->namedtag->setLong("lastPlayed", (int) floor(microtime(true) * 1000));
 
 		if($this->username != "" and $this->namedtag instanceof CompoundTag){
 			$this->server->saveOfflinePlayerData($this->username, $this->namedtag, $async);
diff --git a/src/pocketmine/PocketMine.php b/src/pocketmine/PocketMine.php
index 5c28a70b1..1b5b774d0 100644
--- a/src/pocketmine/PocketMine.php
+++ b/src/pocketmine/PocketMine.php
@@ -129,30 +129,16 @@ namespace pocketmine {
 		define('pocketmine\PATH', dirname(__FILE__, 3) . DIRECTORY_SEPARATOR);
 	}
 
-	$requiredSplVer = "0.0.1";
-	if(!is_file(\pocketmine\PATH . "src/spl/version.php")){
-		echo "[CRITICAL] Cannot find PocketMine-SPL or incompatible version." . PHP_EOL;
-		echo "[CRITICAL] Please update your submodules or use provided builds." . PHP_EOL;
-		exit(1);
-	}elseif(version_compare($requiredSplVer, require(\pocketmine\PATH . "src/spl/version.php")) > 0){
-		echo "[CRITICAL] Incompatible PocketMine-SPL submodule version ($requiredSplVer is required)." . PHP_EOL;
-		echo "[CRITICAL] Please update your submodules or use provided builds." . PHP_EOL;
-		exit(1);
-	}
+	define('pocketmine\COMPOSER_AUTOLOADER_PATH', \pocketmine\PATH . 'vendor/autoload.php');
 
-	if(is_file(\pocketmine\PATH . "vendor/autoload.php")){
-		require_once(\pocketmine\PATH . "vendor/autoload.php");
+	if(is_file(\pocketmine\COMPOSER_AUTOLOADER_PATH)){
+		require_once(\pocketmine\COMPOSER_AUTOLOADER_PATH);
 	}else{
 		echo "[CRITICAL] Composer autoloader not found" . PHP_EOL;
 		echo "[CRITICAL] Please initialize composer dependencies before running." . PHP_EOL;
 		exit(1);
 	}
 
-	if(!class_exists("ClassLoader", false)){
-		require_once(\pocketmine\PATH . "src/spl/ClassLoader.php");
-		require_once(\pocketmine\PATH . "src/spl/BaseClassLoader.php");
-	}
-
 	/*
 	 * We now use the Composer autoloader, but this autoloader is still used by RakLib and for loading plugins.
 	 */
diff --git a/src/pocketmine/block/BurningFurnace.php b/src/pocketmine/block/BurningFurnace.php
index fa652b8dd..6c396aff0 100644
--- a/src/pocketmine/block/BurningFurnace.php
+++ b/src/pocketmine/block/BurningFurnace.php
@@ -77,10 +77,8 @@ class BurningFurnace extends Solid{
 				$furnace = Tile::createTile(Tile::FURNACE, $this->getLevel(), TileFurnace::createNBT($this));
 			}
 
-			if(isset($furnace->namedtag->Lock) and $furnace->namedtag->Lock instanceof StringTag){
-				if($furnace->namedtag->Lock->getValue() !== $item->getCustomName()){
-					return true;
-				}
+			if($furnace->namedtag->hasTag("Lock", StringTag::class) and $furnace->namedtag->getString("Lock") !== $item->getCustomName()){
+				return true;
 			}
 
 			$player->addWindow($furnace->getInventory());
diff --git a/src/pocketmine/block/Chest.php b/src/pocketmine/block/Chest.php
index dd413e737..b318bf25a 100644
--- a/src/pocketmine/block/Chest.php
+++ b/src/pocketmine/block/Chest.php
@@ -126,7 +126,7 @@ class Chest extends Transparent{
 			if(
 				!$this->getSide(Vector3::SIDE_UP)->isTransparent() or
 				($chest->isPaired() and !$chest->getPair()->getBlock()->getSide(Vector3::SIDE_UP)->isTransparent()) or
-				(isset($chest->namedtag->Lock) and $chest->namedtag->Lock instanceof StringTag and $chest->namedtag->Lock->getValue() !== $item->getCustomName())
+				($chest->namedtag->hasTag("Lock", StringTag::class) and $chest->namedtag->getString("Lock") !== $item->getCustomName())
 			){
 				return true;
 			}
diff --git a/src/pocketmine/entity/Entity.php b/src/pocketmine/entity/Entity.php
index 8916ccb87..be19f187c 100644
--- a/src/pocketmine/entity/Entity.php
+++ b/src/pocketmine/entity/Entity.php
@@ -51,12 +51,10 @@ use pocketmine\math\Vector2;
 use pocketmine\math\Vector3;
 use pocketmine\metadata\Metadatable;
 use pocketmine\metadata\MetadataValue;
-use pocketmine\nbt\tag\ByteTag;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\nbt\tag\DoubleTag;
 use pocketmine\nbt\tag\FloatTag;
 use pocketmine\nbt\tag\ListTag;
-use pocketmine\nbt\tag\ShortTag;
 use pocketmine\nbt\tag\StringTag;
 use pocketmine\network\mcpe\protocol\AddEntityPacket;
 use pocketmine\network\mcpe\protocol\EntityEventPacket;
@@ -504,53 +502,36 @@ abstract class Entity extends Location implements Metadatable, EntityIds{
 		$this->server = $level->getServer();
 
 		$this->boundingBox = new AxisAlignedBB(0, 0, 0, 0, 0, 0);
-		$this->setPositionAndRotation(
-			$this->temporalVector->setComponents(
-				$this->namedtag["Pos"][0],
-				$this->namedtag["Pos"][1],
-				$this->namedtag["Pos"][2]
-			),
-			$this->namedtag->Rotation[0],
-			$this->namedtag->Rotation[1]
-		);
 
-		if(isset($this->namedtag->Motion)){
-			$this->setMotion($this->temporalVector->setComponents($this->namedtag["Motion"][0], $this->namedtag["Motion"][1], $this->namedtag["Motion"][2]));
-		}else{
-			$this->setMotion($this->temporalVector->setComponents(0, 0, 0));
+		/** @var float[] $pos */
+		$pos = $this->namedtag->getListTag("Pos")->getAllValues();
+		/** @var float[] $rotation */
+		$rotation = $this->namedtag->getListTag("Rotation")->getAllValues();
+
+		$this->setPositionAndRotation($this->temporalVector->setComponents(...$pos), ...$rotation);
+
+		/** @var float[] $motion */
+		$motion = [0, 0, 0];
+		if($this->namedtag->hasTag("Motion", ListTag::class)){
+			$motion = $this->namedtag->getListTag("Motion")->getAllValues();
 		}
 
+		$this->setMotion($this->temporalVector->setComponents(...$motion));
+
 		$this->resetLastMovements();
 
 		assert(!is_nan($this->x) and !is_infinite($this->x) and !is_nan($this->y) and !is_infinite($this->y) and !is_nan($this->z) and !is_infinite($this->z));
 
-		if(!isset($this->namedtag->FallDistance)){
-			$this->namedtag->FallDistance = new FloatTag("FallDistance", 0);
-		}
-		$this->fallDistance = $this->namedtag["FallDistance"];
+		$this->fallDistance = $this->namedtag->getFloat("FallDistance", 0);
 
-		if(!isset($this->namedtag->Fire)){
-			$this->namedtag->Fire = new ShortTag("Fire", 0);
-		}
-		$this->fireTicks = (int) $this->namedtag["Fire"];
+		$this->fireTicks = $this->namedtag->getShort("Fire", 0);
 		if($this->isOnFire()){
 			$this->setGenericFlag(self::DATA_FLAG_ONFIRE);
 		}
 
-		if(!isset($this->namedtag->Air)){
-			$this->namedtag->Air = new ShortTag("Air", 300);
-		}
-		$this->setDataProperty(self::DATA_AIR, self::DATA_TYPE_SHORT, $this->namedtag["Air"], false);
-
-		if(!isset($this->namedtag->OnGround)){
-			$this->namedtag->OnGround = new ByteTag("OnGround", 0);
-		}
-		$this->onGround = $this->namedtag["OnGround"] !== 0;
-
-		if(!isset($this->namedtag->Invulnerable)){
-			$this->namedtag->Invulnerable = new ByteTag("Invulnerable", 0);
-		}
-		$this->invulnerable = $this->namedtag["Invulnerable"] !== 0;
+		$this->setDataProperty(self::DATA_AIR, self::DATA_TYPE_SHORT, $this->namedtag->getShort("Air", 300), false);
+		$this->onGround = $this->namedtag->getByte("OnGround", 0) !== 0;
+		$this->invulnerable = $this->namedtag->getByte("Invulnerable", 0) !== 0;
 
 		$this->attributeMap = new AttributeMap();
 		$this->addAttributes();
@@ -816,49 +797,46 @@ abstract class Entity extends Location implements Metadatable, EntityIds{
 
 	public function saveNBT(){
 		if(!($this instanceof Player)){
-			$this->namedtag->id = new StringTag("id", $this->getSaveId());
+			$this->namedtag->setString("id", $this->getSaveId(), true);
 
 			if($this->getNameTag() !== ""){
-				$this->namedtag->CustomName = new StringTag("CustomName", $this->getNameTag());
-				$this->namedtag->CustomNameVisible = new ByteTag("CustomNameVisible", $this->isNameTagVisible() ? 1 : 0);
+				$this->namedtag->setString("CustomName", $this->getNameTag());
+				$this->namedtag->setByte("CustomNameVisible", $this->isNameTagVisible() ? 1 : 0);
 			}else{
-				unset($this->namedtag->CustomName);
-				unset($this->namedtag->CustomNameVisible);
+				$this->namedtag->removeTag("CustomName", "CustomNameVisible");
 			}
 		}
 
-		$this->namedtag->Pos = new ListTag("Pos", [
+		$this->namedtag->setTag(new ListTag("Pos", [
 			new DoubleTag("", $this->x),
 			new DoubleTag("", $this->y),
 			new DoubleTag("", $this->z)
-		]);
+		]));
 
-		$this->namedtag->Motion = new ListTag("Motion", [
+		$this->namedtag->setTag(new ListTag("Motion", [
 			new DoubleTag("", $this->motionX),
 			new DoubleTag("", $this->motionY),
 			new DoubleTag("", $this->motionZ)
-		]);
+		]));
 
-		$this->namedtag->Rotation = new ListTag("Rotation", [
+		$this->namedtag->setTag(new ListTag("Rotation", [
 			new FloatTag("", $this->yaw),
 			new FloatTag("", $this->pitch)
-		]);
+		]));
 
-		$this->namedtag->FallDistance = new FloatTag("FallDistance", $this->fallDistance);
-		$this->namedtag->Fire = new ShortTag("Fire", $this->fireTicks);
-		$this->namedtag->Air = new ShortTag("Air", $this->getDataProperty(self::DATA_AIR));
-		$this->namedtag->OnGround = new ByteTag("OnGround", $this->onGround ? 1 : 0);
-		$this->namedtag->Invulnerable = new ByteTag("Invulnerable", $this->invulnerable ? 1 : 0);
+		$this->namedtag->setFloat("FallDistance", $this->fallDistance);
+		$this->namedtag->setShort("Fire", $this->fireTicks);
+		$this->namedtag->setShort("Air", $this->getDataProperty(self::DATA_AIR));
+		$this->namedtag->setByte("OnGround", $this->onGround ? 1 : 0);
+		$this->namedtag->setByte("Invulnerable", $this->invulnerable ? 1 : 0);
 	}
 
 	protected function initEntity(){
 		assert($this->namedtag instanceof CompoundTag);
 
-		if(isset($this->namedtag->CustomName)){
-			$this->setNameTag($this->namedtag["CustomName"]);
-			if(isset($this->namedtag->CustomNameVisible)){
-				$this->setNameTagVisible($this->namedtag["CustomNameVisible"] > 0);
-			}
+		if($this->namedtag->hasTag("CustomName", StringTag::class)){
+			$this->setNameTag($this->namedtag->getString("CustomName"));
+			$this->setNameTagVisible($this->namedtag->getByte("CustomNameVisible", 1) !== 0);
 		}
 
 		$this->scheduleUpdate();
@@ -1709,6 +1687,8 @@ abstract class Entity extends Location implements Metadatable, EntityIds{
 		$radius = $this->width / 2;
 		$this->boundingBox->setBounds($pos->x - $radius, $pos->y, $pos->z - $radius, $pos->x + $radius, $pos->y + $this->height, $pos->z + $radius);
 
+		$this->blocksAround = null;
+
 		$this->checkChunks();
 
 		return true;
diff --git a/src/pocketmine/entity/FallingSand.php b/src/pocketmine/entity/FallingSand.php
index 7ce9f7200..92be9c3d5 100644
--- a/src/pocketmine/entity/FallingSand.php
+++ b/src/pocketmine/entity/FallingSand.php
@@ -53,17 +53,13 @@ class FallingSand extends Entity{
 		parent::initEntity();
 
 		$blockId = 0;
-		$damage = 0;
 
-		if(isset($this->namedtag->TileID)){
-			$blockId = (int) $this->namedtag["TileID"];
-		}elseif(isset($this->namedtag->Tile)){
-			$blockId = (int) $this->namedtag["Tile"];
-			$this->namedtag["TileID"] = new IntTag("TileID", $blockId);
-		}
-
-		if(isset($this->namedtag->Data)){
-			$damage = (int) $this->namedtag["Data"];
+		//TODO: 1.8+ save format
+		if($this->namedtag->hasTag("TileID", IntTag::class)){
+			$blockId = $this->namedtag->getInt("TileID");
+		}elseif($this->namedtag->hasTag("Tile", ByteTag::class)){
+			$blockId = $this->namedtag->getByte("Tile");
+			$this->namedtag->removeTag("Tile");
 		}
 
 		if($blockId === 0){
@@ -71,6 +67,8 @@ class FallingSand extends Entity{
 			return;
 		}
 
+		$damage = $this->namedtag->getByte("Data", 0);
+
 		$this->block = BlockFactory::get($blockId, $damage);
 
 		$this->setDataProperty(self::DATA_VARIANT, self::DATA_TYPE_INT, $this->block->getId() | ($this->block->getDamage() << 8));
@@ -132,7 +130,7 @@ class FallingSand extends Entity{
 	}
 
 	public function saveNBT(){
-		$this->namedtag->TileID = new IntTag("TileID", $this->block->getId());
-		$this->namedtag->Data = new ByteTag("Data", $this->block->getDamage());
+		$this->namedtag->setInt("TileID", $this->block->getId(), true);
+		$this->namedtag->setByte("Data", $this->block->getDamage());
 	}
 }
diff --git a/src/pocketmine/entity/Human.php b/src/pocketmine/entity/Human.php
index f53c494eb..04a8c943a 100644
--- a/src/pocketmine/entity/Human.php
+++ b/src/pocketmine/entity/Human.php
@@ -34,7 +34,6 @@ use pocketmine\item\Item as ItemItem;
 use pocketmine\level\Level;
 use pocketmine\nbt\NBT;
 use pocketmine\nbt\tag\CompoundTag;
-use pocketmine\nbt\tag\FloatTag;
 use pocketmine\nbt\tag\IntTag;
 use pocketmine\nbt\tag\ListTag;
 use pocketmine\nbt\tag\StringTag;
@@ -311,14 +310,15 @@ class Human extends Creature implements ProjectileSource, InventoryHolder{
 	 * For Human entities which are not players, sets their properties such as nametag, skin and UUID from NBT.
 	 */
 	protected function initHumanData(){
-		if(isset($this->namedtag->NameTag)){
-			$this->setNameTag($this->namedtag["NameTag"]);
+		if($this->namedtag->hasTag("NameTag", StringTag::class)){
+			$this->setNameTag($this->namedtag->getString("NameTag"));
 		}
 
-		if(isset($this->namedtag->Skin) and $this->namedtag->Skin instanceof CompoundTag){
+		$skin = $this->namedtag->getCompoundTag("Skin");
+		if($skin !== null){
 			$this->setSkin(new Skin(
-				$this->namedtag->Skin["Name"],
-				$this->namedtag->Skin["Data"]
+				$skin->getString("Name"),
+				$skin->getString("Data")
 			));
 		}
 
@@ -333,71 +333,39 @@ class Human extends Creature implements ProjectileSource, InventoryHolder{
 		$this->inventory = new PlayerInventory($this);
 		$this->initHumanData();
 
-		if(isset($this->namedtag->Inventory) and $this->namedtag->Inventory instanceof ListTag){
-			foreach($this->namedtag->Inventory as $i => $item){
-				if($item["Slot"] >= 0 and $item["Slot"] < 9){ //Hotbar
+		$inventoryTag = $this->namedtag->getListTag("Inventory");
+		if($inventoryTag !== null){
+			/** @var CompoundTag $item */
+			foreach($inventoryTag as $i => $item){
+				$slot = $item->getByte("Slot");
+				if($slot >= 0 and $slot < 9){ //Hotbar
 					//Old hotbar saving stuff, remove it (useless now)
-					unset($this->namedtag->Inventory->{$i});
-				}elseif($item["Slot"] >= 100 and $item["Slot"] < 104){ //Armor
-					$this->inventory->setItem($this->inventory->getSize() + $item["Slot"] - 100, ItemItem::nbtDeserialize($item));
+					unset($inventoryTag[$i]);
+				}elseif($slot >= 100 and $slot < 104){ //Armor
+					$this->inventory->setItem($this->inventory->getSize() + $slot - 100, ItemItem::nbtDeserialize($item));
 				}else{
-					$this->inventory->setItem($item["Slot"] - 9, ItemItem::nbtDeserialize($item));
+					$this->inventory->setItem($slot - 9, ItemItem::nbtDeserialize($item));
 				}
 			}
 		}
 
-		if(isset($this->namedtag->SelectedInventorySlot) and $this->namedtag->SelectedInventorySlot instanceof IntTag){
-			$this->inventory->setHeldItemIndex($this->namedtag->SelectedInventorySlot->getValue(), false);
-		}else{
-			$this->inventory->setHeldItemIndex(0, false);
-		}
+		$this->inventory->setHeldItemIndex($this->namedtag->getInt("SelectedInventorySlot", 0), false);
 
 		parent::initEntity();
 
-		if(!isset($this->namedtag->foodLevel) or !($this->namedtag->foodLevel instanceof IntTag)){
-			$this->namedtag->foodLevel = new IntTag("foodLevel", (int) $this->getFood());
-		}else{
-			$this->setFood((float) $this->namedtag["foodLevel"]);
-		}
+		$this->setFood((float) $this->namedtag->getInt("foodLevel", (int) $this->getFood(), true));
+		$this->setExhaustion($this->namedtag->getFloat("foodExhaustionLevel", $this->getExhaustion(), true));
+		$this->setSaturation($this->namedtag->getFloat("foodSaturationLevel", $this->getSaturation(), true));
+		$this->foodTickTimer = $this->namedtag->getInt("foodTickTimer", $this->foodTickTimer, true);
 
-		if(!isset($this->namedtag->foodExhaustionLevel) or !($this->namedtag->foodExhaustionLevel instanceof FloatTag)){
-			$this->namedtag->foodExhaustionLevel = new FloatTag("foodExhaustionLevel", $this->getExhaustion());
-		}else{
-			$this->setExhaustion((float) $this->namedtag["foodExhaustionLevel"]);
-		}
+		$this->setXpLevel($this->namedtag->getInt("XpLevel", $this->getXpLevel(), true));
+		$this->setXpProgress($this->namedtag->getFloat("XpP", $this->getXpProgress(), true));
+		$this->totalXp = $this->namedtag->getInt("XpTotal", $this->totalXp, true);
 
-		if(!isset($this->namedtag->foodSaturationLevel) or !($this->namedtag->foodSaturationLevel instanceof FloatTag)){
-			$this->namedtag->foodSaturationLevel = new FloatTag("foodSaturationLevel", $this->getSaturation());
+		if($this->namedtag->hasTag("XpSeed", IntTag::class)){
+			$this->xpSeed = $this->namedtag->getInt("XpSeed");
 		}else{
-			$this->setSaturation((float) $this->namedtag["foodSaturationLevel"]);
-		}
-
-		if(!isset($this->namedtag->foodTickTimer) or !($this->namedtag->foodTickTimer instanceof IntTag)){
-			$this->namedtag->foodTickTimer = new IntTag("foodTickTimer", $this->foodTickTimer);
-		}else{
-			$this->foodTickTimer = $this->namedtag["foodTickTimer"];
-		}
-
-		if(!isset($this->namedtag->XpLevel) or !($this->namedtag->XpLevel instanceof IntTag)){
-			$this->namedtag->XpLevel = new IntTag("XpLevel", $this->getXpLevel());
-		}else{
-			$this->setXpLevel((int) $this->namedtag["XpLevel"]);
-		}
-
-		if(!isset($this->namedtag->XpP) or !($this->namedtag->XpP instanceof FloatTag)){
-			$this->namedtag->XpP = new FloatTag("XpP", $this->getXpProgress());
-		}
-
-		if(!isset($this->namedtag->XpTotal) or !($this->namedtag->XpTotal instanceof IntTag)){
-			$this->namedtag->XpTotal = new IntTag("XpTotal", $this->totalXp);
-		}else{
-			$this->totalXp = $this->namedtag["XpTotal"];
-		}
-
-		if(!isset($this->namedtag->XpSeed) or !($this->namedtag->XpSeed instanceof IntTag)){
-			$this->namedtag->XpSeed = new IntTag("XpSeed", $this->xpSeed ?? ($this->xpSeed = mt_rand(-0x80000000, 0x7fffffff)));
-		}else{
-			$this->xpSeed = $this->namedtag["XpSeed"];
+			$this->xpSeed = random_int(INT32_MIN, INT32_MAX);
 		}
 	}
 
@@ -479,19 +447,25 @@ class Human extends Creature implements ProjectileSource, InventoryHolder{
 	public function saveNBT(){
 		parent::saveNBT();
 
-		$this->namedtag->foodLevel = new IntTag("foodLevel", (int) $this->getFood());
-		$this->namedtag->foodExhaustionLevel = new FloatTag("foodExhaustionLevel", $this->getExhaustion());
-		$this->namedtag->foodSaturationLevel = new FloatTag("foodSaturationLevel", $this->getSaturation());
-		$this->namedtag->foodTickTimer = new IntTag("foodTickTimer", $this->foodTickTimer);
+		$this->namedtag->setInt("foodLevel", (int) $this->getFood(), true);
+		$this->namedtag->setFloat("foodExhaustionLevel", $this->getExhaustion(), true);
+		$this->namedtag->setFloat("foodSaturationLevel", $this->getSaturation(), true);
+		$this->namedtag->setInt("foodTickTimer", $this->foodTickTimer);
 
-		$this->namedtag->Inventory = new ListTag("Inventory", [], NBT::TAG_Compound);
+		$this->namedtag->setInt("XpLevel", $this->getXpLevel());
+		$this->namedtag->setFloat("XpP", $this->getXpProgress());
+		$this->namedtag->setInt("XpTotal", $this->totalXp);
+		$this->namedtag->setInt("XpSeed", $this->xpSeed);
+
+		$inventoryTag = new ListTag("Inventory", [], NBT::TAG_Compound);
+		$this->namedtag->setTag($inventoryTag);
 		if($this->inventory !== null){
 			//Normal inventory
 			$slotCount = $this->inventory->getSize() + $this->inventory->getHotbarSize();
 			for($slot = $this->inventory->getHotbarSize(); $slot < $slotCount; ++$slot){
 				$item = $this->inventory->getItem($slot - 9);
 				if(!$item->isNull()){
-					$this->namedtag->Inventory[$slot] = $item->nbtSerialize($slot);
+					$inventoryTag[$slot] = $item->nbtSerialize($slot);
 				}
 			}
 
@@ -499,19 +473,19 @@ class Human extends Creature implements ProjectileSource, InventoryHolder{
 			for($slot = 100; $slot < 104; ++$slot){
 				$item = $this->inventory->getItem($this->inventory->getSize() + $slot - 100);
 				if(!$item->isNull()){
-					$this->namedtag->Inventory[$slot] = $item->nbtSerialize($slot);
+					$inventoryTag[$slot] = $item->nbtSerialize($slot);
 				}
 			}
 
-			$this->namedtag->SelectedInventorySlot = new IntTag("SelectedInventorySlot", $this->inventory->getHeldItemIndex());
+			$this->namedtag->setInt("SelectedInventorySlot", $this->inventory->getHeldItemIndex());
 		}
 
 		if($this->skin !== null){
-			$this->namedtag->Skin = new CompoundTag("Skin", [
+			$this->namedtag->setTag(new CompoundTag("Skin", [
 				//TODO: save cape & geometry
 				new StringTag("Data", $this->skin->getSkinData()),
 				new StringTag("Name", $this->skin->getSkinId())
-			]);
+			]));
 		}
 	}
 
diff --git a/src/pocketmine/entity/Item.php b/src/pocketmine/entity/Item.php
index e8b0b4baf..16536bc2c 100644
--- a/src/pocketmine/entity/Item.php
+++ b/src/pocketmine/entity/Item.php
@@ -27,9 +27,6 @@ use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\event\entity\ItemDespawnEvent;
 use pocketmine\event\entity\ItemSpawnEvent;
 use pocketmine\item\Item as ItemItem;
-use pocketmine\nbt\tag\CompoundTag;
-use pocketmine\nbt\tag\ShortTag;
-use pocketmine\nbt\tag\StringTag;
 use pocketmine\network\mcpe\protocol\AddItemEntityPacket;
 use pocketmine\Player;
 
@@ -59,28 +56,19 @@ class Item extends Entity{
 
 		$this->setMaxHealth(5);
 		$this->setHealth((int) $this->namedtag["Health"]);
-		if(isset($this->namedtag->Age)){
-			$this->age = $this->namedtag["Age"];
-		}
-		if(isset($this->namedtag->PickupDelay)){
-			$this->pickupDelay = $this->namedtag["PickupDelay"];
-		}
-		if(isset($this->namedtag->Owner)){
-			$this->owner = $this->namedtag["Owner"];
-		}
-		if(isset($this->namedtag->Thrower)){
-			$this->thrower = $this->namedtag["Thrower"];
-		}
+		$this->age = $this->namedtag->getShort("Age", $this->age);
+		$this->pickupDelay = $this->namedtag->getShort("PickupDelay", $this->pickupDelay);
+		$this->owner = $this->namedtag->getString("Owner", $this->owner);
+		$this->thrower = $this->namedtag->getString("Thrower", $this->thrower);
 
 
-		if(!isset($this->namedtag->Item)){
+		$itemTag = $this->namedtag->getCompoundTag("Item");
+		if($itemTag === null){
 			$this->close();
 			return;
 		}
 
-		assert($this->namedtag->Item instanceof CompoundTag);
-
-		$this->item = ItemItem::nbtDeserialize($this->namedtag->Item);
+		$this->item = ItemItem::nbtDeserialize($itemTag);
 
 
 		$this->server->getPluginManager()->callEvent(new ItemSpawnEvent($this));
@@ -139,15 +127,15 @@ class Item extends Entity{
 
 	public function saveNBT(){
 		parent::saveNBT();
-		$this->namedtag->Item = $this->item->nbtSerialize(-1, "Item");
-		$this->namedtag->Health = new ShortTag("Health", (int) $this->getHealth());
-		$this->namedtag->Age = new ShortTag("Age", $this->age);
-		$this->namedtag->PickupDelay = new ShortTag("PickupDelay", $this->pickupDelay);
+		$this->namedtag->setTag($this->item->nbtSerialize(-1, "Item"));
+		$this->namedtag->setShort("Health", (int) $this->getHealth());
+		$this->namedtag->setShort("Age", $this->age);
+		$this->namedtag->setShort("PickupDelay", $this->pickupDelay);
 		if($this->owner !== null){
-			$this->namedtag->Owner = new StringTag("Owner", $this->owner);
+			$this->namedtag->setString("Owner", $this->owner);
 		}
 		if($this->thrower !== null){
-			$this->namedtag->Thrower = new StringTag("Thrower", $this->thrower);
+			$this->namedtag->setString("Thrower", $this->thrower);
 		}
 	}
 
diff --git a/src/pocketmine/entity/Living.php b/src/pocketmine/entity/Living.php
index 520e5f7ee..af30d026a 100644
--- a/src/pocketmine/entity/Living.php
+++ b/src/pocketmine/entity/Living.php
@@ -65,29 +65,33 @@ abstract class Living extends Entity implements Damageable{
 	protected function initEntity(){
 		parent::initEntity();
 
-		if(isset($this->namedtag->HealF)){
-			$this->namedtag->Health = new FloatTag("Health", (float) $this->namedtag["HealF"]);
-			unset($this->namedtag->HealF);
-		}elseif(isset($this->namedtag->Health)){
-			if(!($this->namedtag->Health instanceof FloatTag)){
-				$this->namedtag->Health = new FloatTag("Health", (float) $this->namedtag->Health->getValue());
+		$health = $this->getMaxHealth();
+
+		if($this->namedtag->hasTag("HealF", FloatTag::class)){
+			$health = new FloatTag("Health", (float) $this->namedtag["HealF"]);
+			$this->namedtag->removeTag("HealF");
+		}elseif($this->namedtag->hasTag("Health")){
+			$healthTag = $this->namedtag->getTag("Health");
+			$health = (float) $healthTag->getValue(); //Older versions of PocketMine-MP incorrectly saved this as a short instead of a float
+			if(!($healthTag instanceof FloatTag)){
+				$this->namedtag->removeTag("Health");
 			}
-		}else{
-			$this->namedtag->Health = new FloatTag("Health", (float) $this->getMaxHealth());
 		}
 
-		$this->setHealth((float) $this->namedtag["Health"]);
+		$this->setHealth($health);
 
-		if(isset($this->namedtag->ActiveEffects)){
-			foreach($this->namedtag->ActiveEffects->getValue() as $e){
-				$amplifier = Binary::unsignByte($e->Amplifier->getValue()); //0-255 only
+		/** @var CompoundTag[]|ListTag $activeEffectsTag */
+		$activeEffectsTag = $this->namedtag->getListTag("ActiveEffects");
+		if($activeEffectsTag !== null){
+			foreach($activeEffectsTag as $e){
+				$amplifier = Binary::unsignByte($e->getByte("Amplifier")); //0-255 only
 
-				$effect = Effect::getEffect($e["Id"]);
+				$effect = Effect::getEffect($e->getByte("Id"));
 				if($effect === null){
 					continue;
 				}
 
-				$effect->setAmplifier($amplifier)->setDuration($e["Duration"])->setVisible($e["ShowParticles"] > 0);
+				$effect->setAmplifier($amplifier)->setDuration($e->getInt("Duration"))->setVisible($e->getByte("ShowParticles", 1) > 0);
 
 				$this->addEffect($effect);
 			}
@@ -130,7 +134,7 @@ abstract class Living extends Entity implements Damageable{
 
 	public function saveNBT(){
 		parent::saveNBT();
-		$this->namedtag->Health = new FloatTag("Health", $this->getHealth());
+		$this->namedtag->setFloat("Health", $this->getHealth(), true);
 
 		if(count($this->effects) > 0){
 			$effects = [];
@@ -144,9 +148,9 @@ abstract class Living extends Entity implements Damageable{
 				]);
 			}
 
-			$this->namedtag->ActiveEffects = new ListTag("ActiveEffects", $effects);
+			$this->namedtag->setTag(new ListTag("ActiveEffects", $effects));
 		}else{
-			unset($this->namedtag->ActiveEffects);
+			$this->namedtag->removeTag("ActiveEffects");
 		}
 	}
 
diff --git a/src/pocketmine/entity/PrimedTNT.php b/src/pocketmine/entity/PrimedTNT.php
index 783067bbc..3b6489456 100644
--- a/src/pocketmine/entity/PrimedTNT.php
+++ b/src/pocketmine/entity/PrimedTNT.php
@@ -26,7 +26,7 @@ namespace pocketmine\entity;
 use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\event\entity\ExplosionPrimeEvent;
 use pocketmine\level\Explosion;
-use pocketmine\nbt\tag\ByteTag;
+use pocketmine\nbt\tag\ShortTag;
 use pocketmine\network\mcpe\protocol\LevelEventPacket;
 
 class PrimedTNT extends Entity implements Explosive{
@@ -54,8 +54,8 @@ class PrimedTNT extends Entity implements Explosive{
 	protected function initEntity(){
 		parent::initEntity();
 
-		if(isset($this->namedtag->Fuse)){
-			$this->fuse = $this->namedtag["Fuse"];
+		if($this->namedtag->hasTag("Fuse", ShortTag::class)){
+			$this->fuse = $this->namedtag->getShort("Fuse");
 		}else{
 			$this->fuse = 80;
 		}
@@ -73,7 +73,7 @@ class PrimedTNT extends Entity implements Explosive{
 
 	public function saveNBT(){
 		parent::saveNBT();
-		$this->namedtag->Fuse = new ByteTag("Fuse", $this->fuse);
+		$this->namedtag->setShort("Fuse", $this->fuse, true); //older versions incorrectly saved this as a byte
 	}
 
 	public function entityBaseTick(int $tickDiff = 1) : bool{
diff --git a/src/pocketmine/entity/Villager.php b/src/pocketmine/entity/Villager.php
index f50a6a979..87c3ab1d2 100644
--- a/src/pocketmine/entity/Villager.php
+++ b/src/pocketmine/entity/Villager.php
@@ -23,8 +23,6 @@ declare(strict_types=1);
 
 namespace pocketmine\entity;
 
-use pocketmine\nbt\tag\IntTag;
-
 class Villager extends Creature implements NPC, Ageable{
 	const PROFESSION_FARMER = 0;
 	const PROFESSION_LIBRARIAN = 1;
@@ -45,7 +43,7 @@ class Villager extends Creature implements NPC, Ageable{
 		parent::initEntity();
 
 		/** @var int $profession */
-		$profession = $this->namedtag["Profession"] ?? self::PROFESSION_FARMER;
+		$profession = $this->namedtag->getInt("Profession", self::PROFESSION_FARMER);
 
 		if($profession > 4 or $profession < 0){
 			$profession = self::PROFESSION_FARMER;
@@ -56,7 +54,7 @@ class Villager extends Creature implements NPC, Ageable{
 
 	public function saveNBT(){
 		parent::saveNBT();
-		$this->namedtag->Profession = new IntTag("Profession", $this->getProfession());
+		$this->namedtag->setInt("Profession", $this->getProfession());
 	}
 
 	/**
diff --git a/src/pocketmine/entity/projectile/Projectile.php b/src/pocketmine/entity/projectile/Projectile.php
index 7ec665d62..96b23deb1 100644
--- a/src/pocketmine/entity/projectile/Projectile.php
+++ b/src/pocketmine/entity/projectile/Projectile.php
@@ -34,7 +34,6 @@ use pocketmine\level\Level;
 use pocketmine\level\MovingObjectPosition;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\CompoundTag;
-use pocketmine\nbt\tag\ShortTag;
 
 abstract class Projectile extends Entity{
 
@@ -62,9 +61,7 @@ abstract class Projectile extends Entity{
 
 		$this->setMaxHealth(1);
 		$this->setHealth(1);
-		if(isset($this->namedtag->Age)){
-			$this->age = $this->namedtag["Age"];
-		}
+		$this->age = $this->namedtag->getShort("Age", $this->age);
 	}
 
 	public function canCollideWith(Entity $entity) : bool{
@@ -107,7 +104,7 @@ abstract class Projectile extends Entity{
 
 	public function saveNBT(){
 		parent::saveNBT();
-		$this->namedtag->Age = new ShortTag("Age", $this->age);
+		$this->namedtag->setShort("Age", $this->age);
 	}
 
 	protected function applyDragBeforeGravity() : bool{
diff --git a/src/pocketmine/item/Item.php b/src/pocketmine/item/Item.php
index dcaacae67..fffb09628 100644
--- a/src/pocketmine/item/Item.php
+++ b/src/pocketmine/item/Item.php
@@ -481,9 +481,7 @@ class Item implements ItemIds, \JsonSerializable{
 	public function getLore() : array{
 		$display = $this->getNamedTagEntry(self::TAG_DISPLAY);
 		if($display instanceof CompoundTag and ($lore = $display->getListTag(self::TAG_DISPLAY_LORE)) !== null){
-			return array_map(function(StringTag $tag) : string{
-				return $tag->getValue();
-			}, $lore->getValue());
+			return $lore->getAllValues();
 		}
 
 		return [];
diff --git a/src/pocketmine/item/WritableBook.php b/src/pocketmine/item/WritableBook.php
index 907d7188d..16a27ba9d 100644
--- a/src/pocketmine/item/WritableBook.php
+++ b/src/pocketmine/item/WritableBook.php
@@ -23,12 +23,15 @@ declare(strict_types=1);
 
 namespace pocketmine\item;
 
+use pocketmine\nbt\NBT;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\nbt\tag\ListTag;
 use pocketmine\nbt\tag\StringTag;
 
 class WritableBook extends Item{
 
+	const TAG_PAGES = "pages"; //TAG_List<TAG_Compound>
+
 	public function __construct(int $meta = 0){
 		parent::__construct(self::WRITABLE_BOOK, $meta, "Book & Quill");
 	}
@@ -41,7 +44,8 @@ class WritableBook extends Item{
 	 * @return bool
 	 */
 	public function pageExists(int $pageId) : bool{
-		return isset($this->getNamedTag()->pages->{$pageId});
+		$pages = $this->getNamedTag()->getListTag(self::TAG_PAGES);
+		return $pages !== null and isset($pages[$pageId]);
 	}
 
 	/**
@@ -52,10 +56,17 @@ class WritableBook extends Item{
 	 * @return string|null
 	 */
 	public function getPageText(int $pageId) : ?string{
-		if(!$this->pageExists($pageId)){
+		$pages = $this->getNamedTag()->getListTag(self::TAG_PAGES);
+		if($pages === null){
 			return null;
 		}
-		return $this->getNamedTag()->pages->{$pageId}->text->getValue();
+
+		$page = $pages[$pageId] ?? null;
+		if($page instanceof CompoundTag){
+			return $page->getString("text", "");
+		}
+
+		return null;
 	}
 
 	/**
@@ -74,7 +85,11 @@ class WritableBook extends Item{
 		}
 
 		$namedTag = $this->getNamedTag();
-		$namedTag->pages->{$pageId}->text->setValue($pageText);
+		/** @var CompoundTag[]|ListTag $pages */
+		$pages = $namedTag->getListTag(self::TAG_PAGES);
+		assert($pages instanceof ListTag);
+		$pages[$pageId]->setString("text", $pageText);
+
 		$this->setNamedTag($namedTag);
 
 		return $created;
@@ -92,19 +107,19 @@ class WritableBook extends Item{
 		}
 		$namedTag = $this->getNamedTag();
 
-		if(!isset($namedTag->pages) or !($namedTag->pages instanceof ListTag)){
-			$namedTag->pages = new ListTag("pages", []);
-		}
+		/** @var CompoundTag[]|ListTag $pages */
+		$pages = $namedTag->getListTag(self::TAG_PAGES) ?? new ListTag(self::TAG_PAGES, [], NBT::TAG_Compound);
 
 		for($id = 0; $id <= $pageId; $id++){
 			if(!$this->pageExists($id)){
-				$namedTag->pages->{$id} = new CompoundTag("", [
+				$pages[$id] = new CompoundTag("", [
 					new StringTag("text", ""),
 					new StringTag("photoname", "")
 				]);
 			}
 		}
 
+		$namedTag->setTag($pages);
 		$this->setNamedTag($namedTag);
 	}
 
@@ -121,7 +136,7 @@ class WritableBook extends Item{
 		}
 
 		$namedTag = $this->getNamedTag();
-		unset($namedTag->pages->{$pageId});
+		unset($namedTag->getListTag(self::TAG_PAGES)[$pageId]);
 		$this->pushPages($pageId, $namedTag);
 		$this->setNamedTag($namedTag);
 
@@ -186,6 +201,9 @@ class WritableBook extends Item{
 			return false;
 		}
 
+		$pagesTag = $namedTag->getListTag(self::TAG_PAGES);
+		assert($pagesTag !== null);
+
 		$type = $downwards ? -1 : 1;
 		foreach($pages as $key => $page){
 			if(($key <= $pageId and $downwards) or ($key < $pageId and !$downwards)){
@@ -193,9 +211,9 @@ class WritableBook extends Item{
 			}
 
 			if($downwards){
-				unset($namedTag->pages->{$key});
+				unset($pagesTag[$key]);
 			}
-			$namedTag->pages->{$key + $type} = new CompoundTag("", [
+			$pagesTag[$key + $type] = new CompoundTag("", [
 				new StringTag("text", $page->text->getValue()),
 				new StringTag("photoname", "")
 			]);
diff --git a/src/pocketmine/item/WrittenBook.php b/src/pocketmine/item/WrittenBook.php
index 29303fac5..22ff953c1 100644
--- a/src/pocketmine/item/WrittenBook.php
+++ b/src/pocketmine/item/WrittenBook.php
@@ -23,9 +23,6 @@ declare(strict_types=1);
 
 namespace pocketmine\item;
 
-use pocketmine\nbt\tag\IntTag;
-use pocketmine\nbt\tag\StringTag;
-
 class WrittenBook extends WritableBook{
 
 	const GENERATION_ORIGINAL = 0;
@@ -33,6 +30,10 @@ class WrittenBook extends WritableBook{
 	const GENERATION_COPY_OF_COPY = 2;
 	const GENERATION_TATTERED = 3;
 
+	const TAG_GENERATION = "generation"; //TAG_Int
+	const TAG_AUTHOR = "author"; //TAG_String
+	const TAG_TITLE = "title"; //TAG_String
+
 	public function __construct(int $meta = 0){
 		Item::__construct(self::WRITTEN_BOOK, $meta, "Written Book");
 	}
@@ -48,10 +49,7 @@ class WrittenBook extends WritableBook{
 	 * @return int
 	 */
 	public function getGeneration() : int{
-		if(!isset($this->getNamedTag()->generation)) {
-			return -1;
-		}
-		return $this->getNamedTag()->generation->getValue();
+		return $this->getNamedTag()->getInt(self::TAG_GENERATION, -1);
 	}
 
 	/**
@@ -64,12 +62,7 @@ class WrittenBook extends WritableBook{
 			throw new \InvalidArgumentException("Generation \"$generation\" is out of range");
 		}
 		$namedTag = $this->getNamedTag();
-
-		if(isset($namedTag->generation)){
-			$namedTag->generation->setValue($generation);
-		}else{
-			$namedTag->generation = new IntTag("generation", $generation);
-		}
+		$namedTag->setInt(self::TAG_GENERATION, $generation);
 		$this->setNamedTag($namedTag);
 	}
 
@@ -81,10 +74,7 @@ class WrittenBook extends WritableBook{
 	 * @return string
 	 */
 	public function getAuthor() : string{
-		if(!isset($this->getNamedTag()->author)){
-			return "";
-		}
-		return $this->getNamedTag()->author->getValue();
+		return $this->getNamedTag()->getString(self::TAG_AUTHOR, "");
 	}
 
 	/**
@@ -94,11 +84,7 @@ class WrittenBook extends WritableBook{
 	 */
 	public function setAuthor(string $authorName) : void{
 		$namedTag = $this->getNamedTag();
-		if(isset($namedTag->author)){
-			$namedTag->author->setValue($authorName);
-		}else{
-			$namedTag->author = new StringTag("author", $authorName);
-		}
+		$namedTag->setString(self::TAG_AUTHOR, $authorName);
 		$this->setNamedTag($namedTag);
 	}
 
@@ -108,10 +94,7 @@ class WrittenBook extends WritableBook{
 	 * @return string
 	 */
 	public function getTitle() : string{
-		if(!isset($this->getNamedTag()->title)){
-			return "";
-		}
-		return $this->getNamedTag()->title->getValue();
+		return $this->getNamedTag()->getString(self::TAG_TITLE, "");
 	}
 
 	/**
@@ -121,11 +104,7 @@ class WrittenBook extends WritableBook{
 	 */
 	public function setTitle(string $title) : void{
 		$namedTag = $this->getNamedTag();
-		if(isset($namedTag->title)){
-			$namedTag->title->setValue($title);
-		}else{
-			$namedTag->title = new StringTag("title", $title);
-		}
+		$namedTag->setString(self::TAG_TITLE, $title);
 		$this->setNamedTag($namedTag);
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/level/format/io/BaseLevelProvider.php b/src/pocketmine/level/format/io/BaseLevelProvider.php
index eefe7ea98..806f1f0db 100644
--- a/src/pocketmine/level/format/io/BaseLevelProvider.php
+++ b/src/pocketmine/level/format/io/BaseLevelProvider.php
@@ -31,8 +31,6 @@ use pocketmine\level\LevelException;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\NBT;
 use pocketmine\nbt\tag\CompoundTag;
-use pocketmine\nbt\tag\IntTag;
-use pocketmine\nbt\tag\LongTag;
 use pocketmine\nbt\tag\StringTag;
 use pocketmine\scheduler\AsyncTask;
 
@@ -52,19 +50,19 @@ abstract class BaseLevelProvider implements LevelProvider{
 		}
 		$nbt = new NBT(NBT::BIG_ENDIAN);
 		$nbt->readCompressed(file_get_contents($this->getPath() . "level.dat"));
-		$levelData = $nbt->getData();
-		if($levelData->Data instanceof CompoundTag){
-			$this->levelData = $levelData->Data;
+		$levelData = $nbt->getData()->getCompoundTag("Data");
+		if($levelData !== null){
+			$this->levelData = $levelData;
 		}else{
 			throw new LevelException("Invalid level.dat");
 		}
 
-		if(!isset($this->levelData->generatorName)){
-			$this->levelData->generatorName = new StringTag("generatorName", (string) Generator::getGenerator("DEFAULT"));
+		if(!$this->levelData->hasTag("generatorName", StringTag::class)){
+			$this->levelData->setString("generatorName", (string) Generator::getGenerator("DEFAULT"), true);
 		}
 
-		if(!isset($this->levelData->generatorOptions)){
-			$this->levelData->generatorOptions = new StringTag("generatorOptions", "");
+		if(!$this->levelData->hasTag("generatorOptions", StringTag::class)){
+			$this->levelData->setString("generatorOptions", "");
 		}
 	}
 
@@ -81,33 +79,33 @@ abstract class BaseLevelProvider implements LevelProvider{
 	}
 
 	public function getName() : string{
-		return (string) $this->levelData["LevelName"];
+		return $this->levelData->getString("LevelName");
 	}
 
 	public function getTime() : int{
-		return $this->levelData["Time"];
+		return $this->levelData->getLong("Time", 0, true);
 	}
 
 	public function setTime(int $value){
-		$this->levelData->Time = new LongTag("Time", $value);
+		$this->levelData->setLong("Time", $value, true); //some older PM worlds had this in the wrong format
 	}
 
 	public function getSeed() : int{
-		return $this->levelData["RandomSeed"];
+		return $this->levelData->getLong("RandomSeed");
 	}
 
 	public function setSeed(int $value){
-		$this->levelData->RandomSeed = new LongTag("RandomSeed", $value);
+		$this->levelData->setLong("RandomSeed", $value);
 	}
 
 	public function getSpawn() : Vector3{
-		return new Vector3((float) $this->levelData["SpawnX"], (float) $this->levelData["SpawnY"], (float) $this->levelData["SpawnZ"]);
+		return new Vector3($this->levelData->getInt("SpawnX"), $this->levelData->getInt("SpawnY"), $this->levelData->getInt("SpawnZ"));
 	}
 
 	public function setSpawn(Vector3 $pos){
-		$this->levelData->SpawnX = new IntTag("SpawnX", (int) $pos->x);
-		$this->levelData->SpawnY = new IntTag("SpawnY", (int) $pos->y);
-		$this->levelData->SpawnZ = new IntTag("SpawnZ", (int) $pos->z);
+		$this->levelData->setInt("SpawnX", (int) $pos->x);
+		$this->levelData->setInt("SpawnY", (int) $pos->y);
+		$this->levelData->setInt("SpawnZ", (int) $pos->z);
 	}
 
 	public function doGarbageCollection(){
diff --git a/src/pocketmine/level/format/io/leveldb/LevelDB.php b/src/pocketmine/level/format/io/leveldb/LevelDB.php
index 124e52185..0008eddec 100644
--- a/src/pocketmine/level/format/io/leveldb/LevelDB.php
+++ b/src/pocketmine/level/format/io/leveldb/LevelDB.php
@@ -96,26 +96,26 @@ class LevelDB extends BaseLevelProvider{
 			"compression" => LEVELDB_ZLIB_COMPRESSION
 		]);
 
-		if(isset($this->levelData->StorageVersion) and $this->levelData->StorageVersion->getValue() > self::CURRENT_STORAGE_VERSION){
-			throw new LevelException("Specified LevelDB world format version is newer than the version supported by the server");
+		if($this->levelData->getInt("StorageVersion", INT32_MAX, true) > self::CURRENT_STORAGE_VERSION){
+			throw new LevelException("Specified LevelDB world format version is not supported by " . \pocketmine\NAME);
 		}
 
-		if(!isset($this->levelData->generatorName)){
-			if(isset($this->levelData->Generator)){
-				switch((int) $this->levelData->Generator->getValue()){ //Detect correct generator from MCPE data
+		if(!$this->levelData->hasTag("generatorName", StringTag::class)){
+			if($this->levelData->hasTag("Generator", IntTag::class)){
+				switch($this->levelData->getInt("Generator")){ //Detect correct generator from MCPE data
 					case self::GENERATOR_FLAT:
-						$this->levelData->generatorName = new StringTag("generatorName", (string) Generator::getGenerator("FLAT"));
+						$this->levelData->setString("generatorName", (string) Generator::getGenerator("FLAT"));
 						if(($layers = $this->db->get(self::ENTRY_FLAT_WORLD_LAYERS)) !== false){ //Detect existing custom flat layers
 							$layers = trim($layers, "[]");
 						}else{
 							$layers = "7,3,3,2";
 						}
-						$this->levelData->generatorOptions = new StringTag("generatorOptions", "2;" . $layers . ";1");
+						$this->levelData->setString("generatorOptions", "2;" . $layers . ";1");
 						break;
 					case self::GENERATOR_INFINITE:
 						//TODO: add a null generator which does not generate missing chunks (to allow importing back to MCPE and generating more normal terrain without PocketMine messing things up)
-						$this->levelData->generatorName = new StringTag("generatorName", (string) Generator::getGenerator("DEFAULT"));
-						$this->levelData->generatorOptions = new StringTag("generatorOptions", "");
+						$this->levelData->setString("generatorName", (string) Generator::getGenerator("DEFAULT"));
+						$this->levelData->setString("generatorOptions", "");
 						break;
 					case self::GENERATOR_LIMITED:
 						throw new LevelException("Limited worlds are not currently supported");
@@ -123,12 +123,12 @@ class LevelDB extends BaseLevelProvider{
 						throw new LevelException("Unknown LevelDB world format type, this level cannot be loaded");
 				}
 			}else{
-				$this->levelData->generatorName = new StringTag("generatorName", (string) Generator::getGenerator("DEFAULT"));
+				$this->levelData->setString("generatorName", (string) Generator::getGenerator("DEFAULT"));
 			}
 		}
 
-		if(!isset($this->levelData->generatorOptions)){
-			$this->levelData->generatorOptions = new StringTag("generatorOptions", "");
+		if(!$this->levelData->hasTag("generatorOptions", StringTag::class)){
+			$this->levelData->setString("generatorOptions", "");
 		}
 	}
 
@@ -226,8 +226,8 @@ class LevelDB extends BaseLevelProvider{
 	}
 
 	public function saveLevelData(){
-		$this->levelData->NetworkVersion = new IntTag("NetworkVersion", ProtocolInfo::CURRENT_PROTOCOL);
-		$this->levelData->StorageVersion = new IntTag("StorageVersion", self::CURRENT_STORAGE_VERSION);
+		$this->levelData->setInt("NetworkVersion", ProtocolInfo::CURRENT_PROTOCOL);
+		$this->levelData->setInt("StorageVersion", self::CURRENT_STORAGE_VERSION);
 
 		$nbt = new NBT(NBT::LITTLE_ENDIAN);
 		$nbt->setData($this->levelData);
@@ -251,11 +251,11 @@ class LevelDB extends BaseLevelProvider{
 	}
 
 	public function getDifficulty() : int{
-		return isset($this->levelData->Difficulty) ? $this->levelData->Difficulty->getValue() : Level::DIFFICULTY_NORMAL;
+		return $this->levelData->getInt("Difficulty", Level::DIFFICULTY_NORMAL);
 	}
 
 	public function setDifficulty(int $difficulty){
-		$this->levelData->Difficulty = new IntTag("Difficulty", $difficulty);
+		$this->levelData->setInt("Difficulty", $difficulty); //yes, this is intended! (in PE: int, PC: byte)
 	}
 
 	public function getLoadedChunks() : array{
diff --git a/src/pocketmine/level/format/io/region/Anvil.php b/src/pocketmine/level/format/io/region/Anvil.php
index 7e7268a04..56f7c085c 100644
--- a/src/pocketmine/level/format/io/region/Anvil.php
+++ b/src/pocketmine/level/format/io/region/Anvil.php
@@ -28,9 +28,10 @@ use pocketmine\level\format\ChunkException;
 use pocketmine\level\format\io\ChunkUtils;
 use pocketmine\level\format\SubChunk;
 use pocketmine\nbt\NBT;
-use pocketmine\nbt\tag\{
-	ByteArrayTag, ByteTag, CompoundTag, IntArrayTag, IntTag, ListTag, LongTag
-};
+use pocketmine\nbt\tag\ByteArrayTag;
+use pocketmine\nbt\tag\CompoundTag;
+use pocketmine\nbt\tag\IntArrayTag;
+use pocketmine\nbt\tag\ListTag;
 use pocketmine\utils\MainLogger;
 
 class Anvil extends McRegion{
@@ -39,28 +40,29 @@ class Anvil extends McRegion{
 
 	public function nbtSerialize(Chunk $chunk) : string{
 		$nbt = new CompoundTag("Level", []);
-		$nbt->xPos = new IntTag("xPos", $chunk->getX());
-		$nbt->zPos = new IntTag("zPos", $chunk->getZ());
+		$nbt->setInt("xPos", $chunk->getX());
+		$nbt->setInt("zPos", $chunk->getZ());
 
-		$nbt->V = new ByteTag("V", 1);
-		$nbt->LastUpdate = new LongTag("LastUpdate", 0); //TODO
-		$nbt->InhabitedTime = new LongTag("InhabitedTime", 0); //TODO
-		$nbt->TerrainPopulated = new ByteTag("TerrainPopulated", $chunk->isPopulated() ? 1 : 0);
-		$nbt->LightPopulated = new ByteTag("LightPopulated", $chunk->isLightPopulated() ? 1 : 0);
+		$nbt->setByte("V", 1);
+		$nbt->setLong("LastUpdate", 0); //TODO
+		$nbt->setLong("InhabitedTime", 0); //TODO
+		$nbt->setByte("TerrainPopulated", $chunk->isPopulated() ? 1 : 0);
+		$nbt->setByte("LightPopulated", $chunk->isLightPopulated() ? 1 : 0);
 
-		$nbt->Sections = new ListTag("Sections", [], NBT::TAG_Compound);
-		$subChunks = -1;
+		$subChunks = [];
 		foreach($chunk->getSubChunks() as $y => $subChunk){
 			if($subChunk->isEmpty()){
 				continue;
 			}
+
 			$tag = $this->serializeSubChunk($subChunk);
 			$tag->setByte("Y", $y);
-			$nbt->Sections[++$subChunks] = $tag;
+			$subChunks[] = $tag;
 		}
+		$nbt->setTag(new ListTag("Sections", $subChunks, NBT::TAG_Compound));
 
-		$nbt->Biomes = new ByteArrayTag("Biomes", $chunk->getBiomeIdArray());
-		$nbt->HeightMap = new IntArrayTag("HeightMap", $chunk->getHeightMapArray());
+		$nbt->setByteArray("Biomes", $chunk->getBiomeIdArray());
+		$nbt->setIntArray("HeightMap", $chunk->getHeightMapArray());
 
 		$entities = [];
 
@@ -71,7 +73,7 @@ class Anvil extends McRegion{
 			}
 		}
 
-		$nbt->Entities = new ListTag("Entities", $entities, NBT::TAG_Compound);
+		$nbt->setTag(new ListTag("Entities", $entities, NBT::TAG_Compound));
 
 		$tiles = [];
 		foreach($chunk->getTiles() as $tile){
@@ -79,7 +81,7 @@ class Anvil extends McRegion{
 			$tiles[] = $tile->namedtag;
 		}
 
-		$nbt->TileEntities = new ListTag("TileEntities", $tiles, NBT::TAG_Compound);
+		$nbt->setTag(new ListTag("TileEntities", $tiles, NBT::TAG_Compound));
 
 		//TODO: TileTicks
 
@@ -104,43 +106,38 @@ class Anvil extends McRegion{
 		try{
 			$nbt->readCompressed($data);
 
-			$chunk = $nbt->getData();
+			$chunk = $nbt->getData()->getCompoundTag("Level");
 
-			if(!isset($chunk->Level) or !($chunk->Level instanceof CompoundTag)){
+			if($chunk === null){
 				throw new ChunkException("Invalid NBT format");
 			}
 
-			$chunk = $chunk->Level;
-
 			$subChunks = [];
-			if($chunk->Sections instanceof ListTag){
-				foreach($chunk->Sections as $subChunk){
-					if($subChunk instanceof CompoundTag){
-						$subChunks[$subChunk->Y->getValue()] = $this->deserializeSubChunk($subChunk);
-					}
+			$subChunksTag = $chunk->getListTag("Sections") ?? [];
+			foreach($subChunksTag as $subChunk){
+				if($subChunk instanceof CompoundTag){
+					$subChunks[$subChunk->getByte("Y")] = $this->deserializeSubChunk($subChunk);
 				}
 			}
 
-			if(isset($chunk->BiomeColors)){
-				$biomeIds = ChunkUtils::convertBiomeColors($chunk->BiomeColors->getValue()); //Convert back to original format
-			}elseif(isset($chunk->Biomes)){
-				$biomeIds = $chunk->Biomes->getValue();
+			if($chunk->hasTag("BiomeColors", IntArrayTag::class)){
+				$biomeIds = ChunkUtils::convertBiomeColors($chunk->getIntArray("BiomeColors")); //Convert back to original format
 			}else{
-				$biomeIds = "";
+				$biomeIds = $chunk->getByteArray("Biomes", "", true);
 			}
 
 			$result = new Chunk(
-				$chunk["xPos"],
-				$chunk["zPos"],
+				$chunk->getInt("xPos"),
+				$chunk->getInt("zPos"),
 				$subChunks,
-				isset($chunk->Entities) ? $chunk->Entities->getValue() : [],
-				isset($chunk->TileEntities) ? $chunk->TileEntities->getValue() : [],
+				$chunk->hasTag("Entities", ListTag::class) ? $chunk->getListTag("Entities")->getValue() : [],
+				$chunk->hasTag("TileEntities", ListTag::class) ? $chunk->getListTag("TileEntities")->getValue() : [],
 				$biomeIds,
-				isset($chunk->HeightMap) ? $chunk->HeightMap->getValue() : []
+				$chunk->getIntArray("HeightMap", [])
 			);
-			$result->setLightPopulated(isset($chunk->LightPopulated) ? ((bool) $chunk->LightPopulated->getValue()) : false);
-			$result->setPopulated(isset($chunk->TerrainPopulated) ? ((bool) $chunk->TerrainPopulated->getValue()) : false);
-			$result->setGenerated(true);
+			$result->setLightPopulated($chunk->getByte("LightPopulated", 0) !== 0);
+			$result->setPopulated($chunk->getByte("TerrainPopulated", 0) !== 0);
+			$result->setGenerated();
 			return $result;
 		}catch(\Throwable $e){
 			MainLogger::getLogger()->logException($e);
@@ -150,10 +147,10 @@ class Anvil extends McRegion{
 
 	protected function deserializeSubChunk(CompoundTag $subChunk) : SubChunk{
 		return new SubChunk(
-			ChunkUtils::reorderByteArray($subChunk->Blocks->getValue()),
-			ChunkUtils::reorderNibbleArray($subChunk->Data->getValue()),
-			ChunkUtils::reorderNibbleArray($subChunk->SkyLight->getValue(), "\xff"),
-			ChunkUtils::reorderNibbleArray($subChunk->BlockLight->getValue())
+			ChunkUtils::reorderByteArray($subChunk->getByteArray("Blocks")),
+			ChunkUtils::reorderNibbleArray($subChunk->getByteArray("Data")),
+			ChunkUtils::reorderNibbleArray($subChunk->getByteArray("SkyLight"), "\xff"),
+			ChunkUtils::reorderNibbleArray($subChunk->getByteArray("BlockLight"))
 		);
 	}
 
diff --git a/src/pocketmine/level/format/io/region/McRegion.php b/src/pocketmine/level/format/io/region/McRegion.php
index 2c505ce03..c5dd16505 100644
--- a/src/pocketmine/level/format/io/region/McRegion.php
+++ b/src/pocketmine/level/format/io/region/McRegion.php
@@ -53,12 +53,12 @@ class McRegion extends BaseLevelProvider{
 	 */
 	public function nbtSerialize(Chunk $chunk) : string{
 		$nbt = new CompoundTag("Level", []);
-		$nbt->xPos = new IntTag("xPos", $chunk->getX());
-		$nbt->zPos = new IntTag("zPos", $chunk->getZ());
+		$nbt->setInt("xPos", $chunk->getX());
+		$nbt->setInt("zPos", $chunk->getZ());
 
-		$nbt->LastUpdate = new LongTag("LastUpdate", 0); //TODO
-		$nbt->TerrainPopulated = new ByteTag("TerrainPopulated", $chunk->isPopulated() ? 1 : 0);
-		$nbt->LightPopulated = new ByteTag("LightPopulated", $chunk->isLightPopulated() ? 1 : 0);
+		$nbt->setLong("LastUpdate", 0); //TODO
+		$nbt->setByte("TerrainPopulated", $chunk->isPopulated() ? 1 : 0);
+		$nbt->setByte("LightPopulated", $chunk->isLightPopulated() ? 1 : 0);
 
 		$ids = "";
 		$data = "";
@@ -77,13 +77,13 @@ class McRegion extends BaseLevelProvider{
 			}
 		}
 
-		$nbt->Blocks = new ByteArrayTag("Blocks", $ids);
-		$nbt->Data = new ByteArrayTag("Data", $data);
-		$nbt->SkyLight = new ByteArrayTag("SkyLight", $skyLight);
-		$nbt->BlockLight = new ByteArrayTag("BlockLight", $blockLight);
+		$nbt->setByteArray("Blocks", $ids);
+		$nbt->setByteArray("Data", $data);
+		$nbt->setByteArray("SkyLight", $skyLight);
+		$nbt->setByteArray("BlockLight", $blockLight);
 
-		$nbt->Biomes = new ByteArrayTag("Biomes", $chunk->getBiomeIdArray()); //doesn't exist in regular McRegion, this is here for PocketMine-MP only
-		$nbt->HeightMap = new ByteArrayTag("HeightMap", pack("C*", ...$chunk->getHeightMapArray()));
+		$nbt->setByteArray("Biomes", $chunk->getBiomeIdArray()); //doesn't exist in regular McRegion, this is here for PocketMine-MP only
+		$nbt->setByteArray("HeightMap", pack("C*", ...$chunk->getHeightMapArray())); //this is ByteArray in McRegion, but IntArray in Anvil (due to raised build height)
 
 		$entities = [];
 
@@ -94,7 +94,7 @@ class McRegion extends BaseLevelProvider{
 			}
 		}
 
-		$nbt->Entities = new ListTag("Entities", $entities, NBT::TAG_Compound);
+		$nbt->setTag(new ListTag("Entities", $entities, NBT::TAG_Compound));
 
 		$tiles = [];
 		foreach($chunk->getTiles() as $tile){
@@ -102,7 +102,7 @@ class McRegion extends BaseLevelProvider{
 			$tiles[] = $tile->namedtag;
 		}
 
-		$nbt->TileEntities = new ListTag("TileEntities", $tiles, NBT::TAG_Compound);
+		$nbt->setTag(new ListTag("TileEntities", $tiles, NBT::TAG_Compound));
 
 		$writer = new NBT(NBT::BIG_ENDIAN);
 		$nbt->setName("Level");
@@ -281,11 +281,11 @@ class McRegion extends BaseLevelProvider{
 	}
 
 	public function getDifficulty() : int{
-		return isset($this->levelData->Difficulty) ? $this->levelData->Difficulty->getValue() : Level::DIFFICULTY_NORMAL;
+		return $this->levelData->getByte("Difficulty", Level::DIFFICULTY_NORMAL);
 	}
 
 	public function setDifficulty(int $difficulty){
-		$this->levelData->Difficulty = new ByteTag("Difficulty", $difficulty);
+		$this->levelData->setByte("Difficulty", $difficulty);
 	}
 
 	public function getChunk(int $chunkX, int $chunkZ, bool $create = false){
diff --git a/src/pocketmine/level/format/io/region/PMAnvil.php b/src/pocketmine/level/format/io/region/PMAnvil.php
index 6e7cef20d..9b6a88749 100644
--- a/src/pocketmine/level/format/io/region/PMAnvil.php
+++ b/src/pocketmine/level/format/io/region/PMAnvil.php
@@ -23,14 +23,9 @@ declare(strict_types=1);
 
 namespace pocketmine\level\format\io\region;
 
-use pocketmine\level\format\Chunk;
-use pocketmine\level\format\ChunkException;
 use pocketmine\level\format\SubChunk;
-use pocketmine\nbt\NBT;
-use pocketmine\nbt\tag\{
-	ByteArrayTag, ByteTag, CompoundTag, IntArrayTag, IntTag, ListTag, LongTag
-};
-use pocketmine\utils\MainLogger;
+use pocketmine\nbt\tag\ByteArrayTag;
+use pocketmine\nbt\tag\CompoundTag;
 
 /**
  * This format is exactly the same as the PC Anvil format, with the only difference being that the stored data order
@@ -51,10 +46,10 @@ class PMAnvil extends Anvil{
 
 	protected function deserializeSubChunk(CompoundTag $subChunk) : SubChunk{
 		return new SubChunk(
-			$subChunk->Blocks->getValue(),
-			$subChunk->Data->getValue(),
-			$subChunk->SkyLight->getValue(),
-			$subChunk->BlockLight->getValue()
+			$subChunk->getByteArray("Blocks"),
+			$subChunk->getByteArray("Data"),
+			$subChunk->getByteArray("SkyLight"),
+			$subChunk->getByteArray("BlockLight")
 		);
 	}
 
diff --git a/src/pocketmine/nbt/tag/ListTag.php b/src/pocketmine/nbt/tag/ListTag.php
index bb0501ce5..ebff8ab11 100644
--- a/src/pocketmine/nbt/tag/ListTag.php
+++ b/src/pocketmine/nbt/tag/ListTag.php
@@ -88,6 +88,23 @@ class ListTag extends NamedTag implements \ArrayAccess, \Countable{
 		return $count;
 	}
 
+	public function getAllValues() : array{
+		$result = [];
+		foreach($this as $tag){
+			if(!($tag instanceof NamedTag)){
+				continue;
+			}
+
+			if($tag instanceof \ArrayAccess){
+				$result[] = $tag;
+			}else{
+				$result[] = $tag->getValue();
+			}
+		}
+
+		return $result;
+	}
+
 	public function offsetExists($offset){
 		return isset($this->{$offset});
 	}
diff --git a/src/pocketmine/network/mcpe/RakLibInterface.php b/src/pocketmine/network/mcpe/RakLibInterface.php
index 7d888b448..dd9ece852 100644
--- a/src/pocketmine/network/mcpe/RakLibInterface.php
+++ b/src/pocketmine/network/mcpe/RakLibInterface.php
@@ -65,7 +65,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 	public function __construct(Server $server){
 		$this->server = $server;
 
-		$this->rakLib = new RakLibServer($this->server->getLogger(), $this->server->getLoader(), $this->server->getPort(), $this->server->getIp() === "" ? "0.0.0.0" : $this->server->getIp(), false);
+		$this->rakLib = new RakLibServer($this->server->getLogger(), \pocketmine\COMPOSER_AUTOLOADER_PATH, $this->server->getPort(), $this->server->getIp() === "" ? "0.0.0.0" : $this->server->getIp(), false);
 		$this->interface = new ServerHandler($this->rakLib, $this);
 	}
 
diff --git a/src/pocketmine/tile/Spawnable.php b/src/pocketmine/tile/Spawnable.php
index 076ce3412..598f6211c 100644
--- a/src/pocketmine/tile/Spawnable.php
+++ b/src/pocketmine/tile/Spawnable.php
@@ -107,10 +107,10 @@ abstract class Spawnable extends Tile{
 	 */
 	final public function getSpawnCompound() : CompoundTag{
 		$nbt = new CompoundTag("", [
-			$this->namedtag->getTag("id"),
-			$this->namedtag->getTag("x"),
-			$this->namedtag->getTag("y"),
-			$this->namedtag->getTag("z")
+			$this->namedtag->getTag(self::TAG_ID),
+			$this->namedtag->getTag(self::TAG_X),
+			$this->namedtag->getTag(self::TAG_Y),
+			$this->namedtag->getTag(self::TAG_Z)
 		]);
 		$this->addAdditionalSpawnData($nbt);
 		return $nbt;
diff --git a/src/pocketmine/tile/Tile.php b/src/pocketmine/tile/Tile.php
index 5e1efeeb3..a03134d5a 100644
--- a/src/pocketmine/tile/Tile.php
+++ b/src/pocketmine/tile/Tile.php
@@ -44,6 +44,11 @@ use pocketmine\Server;
 
 abstract class Tile extends Position{
 
+	const TAG_ID = "id";
+	const TAG_X = "x";
+	const TAG_Y = "y";
+	const TAG_Z = "z";
+
 	const BREWING_STAND = "BrewingStand";
 	const CHEST = "Chest";
 	const ENCHANT_TABLE = "EnchantTable";
@@ -136,14 +141,14 @@ abstract class Tile extends Position{
 		$this->namedtag = $nbt;
 		$this->server = $level->getServer();
 		$this->setLevel($level);
-		$this->chunk = $level->getChunk($this->namedtag->getInt("x") >> 4, $this->namedtag->getInt("z") >> 4, false);
+		$this->chunk = $level->getChunk($this->namedtag->getInt(self::TAG_X) >> 4, $this->namedtag->getInt(self::TAG_Z) >> 4, false);
 		assert($this->chunk !== null);
 
 		$this->name = "";
 		$this->id = Tile::$tileCount++;
-		$this->x = $this->namedtag->getInt("x");
-		$this->y = $this->namedtag->getInt("y");
-		$this->z = $this->namedtag->getInt("z");
+		$this->x = $this->namedtag->getInt(self::TAG_X);
+		$this->y = $this->namedtag->getInt(self::TAG_Y);
+		$this->z = $this->namedtag->getInt(self::TAG_Z);
 
 		$this->chunk->addTile($this);
 		$this->getLevel()->addTile($this);
@@ -154,10 +159,10 @@ abstract class Tile extends Position{
 	}
 
 	public function saveNBT() : void{
-		$this->namedtag->setString("id", static::getSaveId());
-		$this->namedtag->setInt("x", $this->x);
-		$this->namedtag->setInt("y", $this->y);
-		$this->namedtag->setInt("z", $this->z);
+		$this->namedtag->setString(self::TAG_ID, static::getSaveId());
+		$this->namedtag->setInt(self::TAG_X, $this->x);
+		$this->namedtag->setInt(self::TAG_Y, $this->y);
+		$this->namedtag->setInt(self::TAG_Z, $this->z);
 	}
 
 	public function getNBT() : CompoundTag{
@@ -167,7 +172,7 @@ abstract class Tile extends Position{
 	public function getCleanedNBT() : ?CompoundTag{
 		$this->saveNBT();
 		$tag = clone $this->namedtag;
-		$tag->removeTag("x", "y", "z", "id");
+		$tag->removeTag(self::TAG_X, self::TAG_Y, self::TAG_Z, self::TAG_ID);
 		if($tag->getCount() > 0){
 			return $tag;
 		}else{
@@ -187,10 +192,10 @@ abstract class Tile extends Position{
 	 */
 	public static function createNBT(Vector3 $pos, ?int $face = null, ?Item $item = null, ?Player $player = null) : CompoundTag{
 		$nbt = new CompoundTag("", [
-			new StringTag("id", static::getSaveId()),
-			new IntTag("x", (int) $pos->x),
-			new IntTag("y", (int) $pos->y),
-			new IntTag("z", (int) $pos->z)
+			new StringTag(self::TAG_ID, static::getSaveId()),
+			new IntTag(self::TAG_X, (int) $pos->x),
+			new IntTag(self::TAG_Y, (int) $pos->y),
+			new IntTag(self::TAG_Z, (int) $pos->z)
 		]);
 
 		static::createAdditionalNBT($nbt, $pos, $face, $item, $player);
diff --git a/src/raklib b/src/raklib
deleted file mode 160000
index 0e2611533..000000000
--- a/src/raklib
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 0e26115330808b91ac3ab0b39e54fc9f9f679189
diff --git a/src/spl b/src/spl
deleted file mode 160000
index cf7738721..000000000
--- a/src/spl
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit cf7738721e7342c018a91ad300108b2dd95c7224