diff --git a/src/pocketmine/level/format/io/LevelProvider.php b/src/pocketmine/level/format/io/LevelProvider.php
index ea09f633e..cb5838b01 100644
--- a/src/pocketmine/level/format/io/LevelProvider.php
+++ b/src/pocketmine/level/format/io/LevelProvider.php
@@ -63,7 +63,7 @@ interface LevelProvider{
 	 * @param string  $generator
 	 * @param array[] $options
 	 */
-	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []);
+	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []) : void;
 
 	/**
 	 * Saves a chunk (usually to disk).
@@ -88,7 +88,7 @@ interface LevelProvider{
 	/**
 	 * Performs garbage collection in the level provider, such as cleaning up regions in Region-based worlds.
 	 */
-	public function doGarbageCollection();
+	public function doGarbageCollection() : void;
 
 	/**
 	 * Returns information about the world
@@ -100,7 +100,7 @@ interface LevelProvider{
 	/**
 	 * Performs cleanups necessary when the level provider is closed and no longer needed.
 	 */
-	public function close();
+	public function close() : void;
 
 	/**
 	 * Returns a generator which yields all the chunks in this level.
diff --git a/src/pocketmine/level/format/io/data/BedrockLevelData.php b/src/pocketmine/level/format/io/data/BedrockLevelData.php
index dcc98ffce..320d101a5 100644
--- a/src/pocketmine/level/format/io/data/BedrockLevelData.php
+++ b/src/pocketmine/level/format/io/data/BedrockLevelData.php
@@ -45,7 +45,7 @@ class BedrockLevelData extends BaseNbtLevelData{
 	public const GENERATOR_INFINITE = 1;
 	public const GENERATOR_FLAT = 2;
 
-	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []){
+	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []) : void{
 		switch($generator){
 			case Flat::class:
 				$generatorType = self::GENERATOR_FLAT;
diff --git a/src/pocketmine/level/format/io/data/JavaLevelData.php b/src/pocketmine/level/format/io/data/JavaLevelData.php
index a8ecf9beb..2847a46c6 100644
--- a/src/pocketmine/level/format/io/data/JavaLevelData.php
+++ b/src/pocketmine/level/format/io/data/JavaLevelData.php
@@ -35,7 +35,7 @@ use pocketmine\nbt\tag\StringTag;
 
 class JavaLevelData extends BaseNbtLevelData{
 
-	public static function generate(string $path, string $name, int $seed, string $generator, array $options = [], int $version = 19133){
+	public static function generate(string $path, string $name, int $seed, string $generator, array $options = [], int $version = 19133) : void{
 		//TODO, add extra details
 		$levelData = new CompoundTag("Data", [
 			new ByteTag("hardcore", ($options["hardcore"] ?? false) === true ? 1 : 0),
diff --git a/src/pocketmine/level/format/io/leveldb/LevelDB.php b/src/pocketmine/level/format/io/leveldb/LevelDB.php
index f721f97b2..2cabde657 100644
--- a/src/pocketmine/level/format/io/leveldb/LevelDB.php
+++ b/src/pocketmine/level/format/io/leveldb/LevelDB.php
@@ -68,7 +68,7 @@ class LevelDB extends BaseLevelProvider{
 	/** @var \LevelDB */
 	protected $db;
 
-	private static function checkForLevelDBExtension(){
+	private static function checkForLevelDBExtension() : void{
 		if(!extension_loaded('leveldb')){
 			throw new LevelException("The leveldb PHP extension is required to use this world format");
 		}
@@ -103,7 +103,7 @@ class LevelDB extends BaseLevelProvider{
 		return file_exists($path . "/level.dat") and is_dir($path . "/db/");
 	}
 
-	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []){
+	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []) : void{
 		self::checkForLevelDBExtension();
 
 		if(!file_exists($path . "/db")){
@@ -323,7 +323,7 @@ class LevelDB extends BaseLevelProvider{
 	 * @param CompoundTag[] $targets
 	 * @param string        $index
 	 */
-	private function writeTags(array $targets, string $index){
+	private function writeTags(array $targets, string $index) : void{
 		if(!empty($targets)){
 			$nbt = new LittleEndianNBTStream();
 			$this->db->put($index, $nbt->write($targets));
@@ -347,11 +347,11 @@ class LevelDB extends BaseLevelProvider{
 		return $this->db->get(LevelDB::chunkIndex($chunkX, $chunkZ) . self::TAG_VERSION) !== false;
 	}
 
-	public function doGarbageCollection(){
+	public function doGarbageCollection() : void{
 
 	}
 
-	public function close(){
+	public function close() : void{
 		$this->db->close();
 	}
 
diff --git a/src/pocketmine/level/format/io/region/RegionLevelProvider.php b/src/pocketmine/level/format/io/region/RegionLevelProvider.php
index fad5ff3eb..6c9e637f5 100644
--- a/src/pocketmine/level/format/io/region/RegionLevelProvider.php
+++ b/src/pocketmine/level/format/io/region/RegionLevelProvider.php
@@ -57,7 +57,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 		return false;
 	}
 
-	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []){
+	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []) : void{
 		if(!file_exists($path)){
 			mkdir($path, 0777, true);
 		}
@@ -76,7 +76,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 		return new JavaLevelData($this->getPath() . "level.dat");
 	}
 
-	public function doGarbageCollection(){
+	public function doGarbageCollection() : void{
 		$limit = time() - 300;
 		foreach($this->regions as $index => $region){
 			if($region->lastUsed <= $limit){
@@ -92,7 +92,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 	 * @param int &$regionX
 	 * @param int &$regionZ
 	 */
-	public static function getRegionIndex(int $chunkX, int $chunkZ, &$regionX, &$regionZ){
+	public static function getRegionIndex(int $chunkX, int $chunkZ, &$regionX, &$regionZ) : void{
 		$regionX = $chunkX >> 5;
 		$regionZ = $chunkZ >> 5;
 	}
@@ -103,7 +103,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 	 *
 	 * @return RegionLoader|null
 	 */
-	protected function getRegion(int $regionX, int $regionZ){
+	protected function getRegion(int $regionX, int $regionZ) : ?RegionLoader{
 		return $this->regions[Level::chunkHash($regionX, $regionZ)] ?? null;
 	}
 
@@ -123,7 +123,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 	 * @param int $regionX
 	 * @param int $regionZ
 	 */
-	protected function loadRegion(int $regionX, int $regionZ){
+	protected function loadRegion(int $regionX, int $regionZ) : void{
 		if(!isset($this->regions[$index = Level::chunkHash($regionX, $regionZ)])){
 			$path = $this->pathToRegion($regionX, $regionZ);
 
@@ -148,7 +148,7 @@ abstract class RegionLevelProvider extends BaseLevelProvider{
 		}
 	}
 
-	public function close(){
+	public function close() : void{
 		foreach($this->regions as $index => $region){
 			$region->close();
 			unset($this->regions[$index]);
diff --git a/src/pocketmine/level/format/io/region/RegionLoader.php b/src/pocketmine/level/format/io/region/RegionLoader.php
index dc6ee97c7..baa84cfe0 100644
--- a/src/pocketmine/level/format/io/region/RegionLoader.php
+++ b/src/pocketmine/level/format/io/region/RegionLoader.php
@@ -53,7 +53,7 @@ class RegionLoader{
 		$this->filePath = $filePath;
 	}
 
-	public function open(){
+	public function open() : void{
 		$exists = file_exists($this->filePath);
 		if(!$exists){
 			touch($this->filePath);
@@ -138,7 +138,7 @@ class RegionLoader{
 		return $this->isChunkGenerated(self::getChunkOffset($x, $z));
 	}
 
-	public function writeChunk(int $x, int $z, string $chunkData){
+	public function writeChunk(int $x, int $z, string $chunkData) : void{
 		$this->lastUsed = time();
 
 		$length = strlen($chunkData) + 1;
@@ -167,7 +167,7 @@ class RegionLoader{
 		}
 	}
 
-	public function removeChunk(int $x, int $z){
+	public function removeChunk(int $x, int $z) : void{
 		$index = self::getChunkOffset($x, $z);
 		$this->locationTable[$index][0] = 0;
 		$this->locationTable[$index][1] = 0;
@@ -182,7 +182,7 @@ class RegionLoader{
 	 *
 	 * @param bool $writeHeader
 	 */
-	public function close(bool $writeHeader = true){
+	public function close(bool $writeHeader = true) : void{
 		if(is_resource($this->filePointer)){
 			if($writeHeader){
 				$this->writeLocationTable();
@@ -267,7 +267,7 @@ class RegionLoader{
 		return $shift;
 	}
 
-	protected function loadLocationTable(){
+	protected function loadLocationTable() : void{
 		fseek($this->filePointer, 0);
 		$this->lastSector = 1;
 
@@ -301,7 +301,7 @@ class RegionLoader{
 		fseek($this->filePointer, 0);
 	}
 
-	private function writeLocationTable(){
+	private function writeLocationTable() : void{
 		$write = [];
 
 		for($i = 0; $i < 1024; ++$i){
@@ -314,14 +314,14 @@ class RegionLoader{
 		fwrite($this->filePointer, pack("N*", ...$write), 4096 * 2);
 	}
 
-	protected function writeLocationIndex($index){
+	protected function writeLocationIndex(int $index) : void{
 		fseek($this->filePointer, $index << 2);
 		fwrite($this->filePointer, Binary::writeInt(($this->locationTable[$index][0] << 8) | $this->locationTable[$index][1]), 4);
 		fseek($this->filePointer, 4096 + ($index << 2));
 		fwrite($this->filePointer, Binary::writeInt($this->locationTable[$index][2]), 4);
 	}
 
-	protected function createBlank(){
+	protected function createBlank() : void{
 		fseek($this->filePointer, 0);
 		ftruncate($this->filePointer, 8192); // this fills the file with the null byte
 		$this->lastSector = 1;