diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index a32f67086..fdd3f9f81 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -183,7 +183,7 @@ class Server{
 	public const BROADCAST_CHANNEL_ADMINISTRATIVE = "pocketmine.broadcast.admin";
 	public const BROADCAST_CHANNEL_USERS = "pocketmine.broadcast.user";
 
-	/** @var Server */
+	/** @var Server|null */
 	private static $instance = null;
 
 	/** @var \Threaded|null */
@@ -346,7 +346,7 @@ class Server{
 	/** @var Level[] */
 	private $levels = [];
 
-	/** @var Level */
+	/** @var Level|null */
 	private $levelDefault = null;
 
 	public function getName() : string{
diff --git a/src/pocketmine/command/Command.php b/src/pocketmine/command/Command.php
index 3c9c5f7a2..4bb0352ef 100644
--- a/src/pocketmine/command/Command.php
+++ b/src/pocketmine/command/Command.php
@@ -65,11 +65,11 @@ abstract class Command{
 	/** @var string|null */
 	private $permission = null;
 
-	/** @var string */
+	/** @var string|null */
 	private $permissionMessage = null;
 
-	/** @var TimingsHandler */
-	public $timings;
+	/** @var TimingsHandler|null */
+	public $timings = null;
 
 	/**
 	 * @param string[] $aliases
diff --git a/src/pocketmine/item/Item.php b/src/pocketmine/item/Item.php
index c469755bc..5ad333758 100644
--- a/src/pocketmine/item/Item.php
+++ b/src/pocketmine/item/Item.php
@@ -60,7 +60,7 @@ class Item implements ItemIds, \JsonSerializable{
 	public const TAG_DISPLAY_NAME = "Name";
 	public const TAG_DISPLAY_LORE = "Lore";
 
-	/** @var LittleEndianNBTStream */
+	/** @var LittleEndianNBTStream|null */
 	private static $cachedParser = null;
 
 	private static function parseCompoundTag(string $tag) : CompoundTag{
diff --git a/src/pocketmine/level/Explosion.php b/src/pocketmine/level/Explosion.php
index 08b049661..a2f7684c6 100644
--- a/src/pocketmine/level/Explosion.php
+++ b/src/pocketmine/level/Explosion.php
@@ -60,14 +60,14 @@ class Explosion{
 	public $affectedBlocks = [];
 	/** @var float */
 	public $stepLen = 0.3;
-	/** @var Entity|Block */
+	/** @var Entity|Block|null */
 	private $what;
 
 	/** @var SubChunkIteratorManager */
 	private $subChunkHandler;
 
 	/**
-	 * @param Entity|Block $what
+	 * @param Entity|Block|null $what
 	 */
 	public function __construct(Position $center, float $size, $what = null){
 		if(!$center->isValid()){
diff --git a/src/pocketmine/network/mcpe/protocol/DataPacket.php b/src/pocketmine/network/mcpe/protocol/DataPacket.php
index b329a179e..7f8aa2fb7 100644
--- a/src/pocketmine/network/mcpe/protocol/DataPacket.php
+++ b/src/pocketmine/network/mcpe/protocol/DataPacket.php
@@ -41,7 +41,7 @@ abstract class DataPacket extends NetworkBinaryStream{
 
 	/** @var bool */
 	public $isEncoded = false;
-	/** @var CachedEncapsulatedPacket */
+	/** @var CachedEncapsulatedPacket|null */
 	public $__encapsulatedPacket = null;
 
 	/** @var int */
diff --git a/src/pocketmine/network/mcpe/protocol/LoginPacket.php b/src/pocketmine/network/mcpe/protocol/LoginPacket.php
index a8ad473bf..5e8a5a8ed 100644
--- a/src/pocketmine/network/mcpe/protocol/LoginPacket.php
+++ b/src/pocketmine/network/mcpe/protocol/LoginPacket.php
@@ -45,8 +45,8 @@ class LoginPacket extends DataPacket{
 	public $clientUUID;
 	/** @var int */
 	public $clientId;
-	/** @var string */
-	public $xuid;
+	/** @var string|null */
+	public $xuid = null;
 	/** @var string */
 	public $identityPublicKey;
 	/** @var string */
diff --git a/src/pocketmine/permission/PermissibleBase.php b/src/pocketmine/permission/PermissibleBase.php
index 0b7e44e52..f8f646931 100644
--- a/src/pocketmine/permission/PermissibleBase.php
+++ b/src/pocketmine/permission/PermissibleBase.php
@@ -32,7 +32,7 @@ class PermissibleBase implements Permissible{
 	/** @var ServerOperator */
 	private $opable;
 
-	/** @var Permissible */
+	/** @var Permissible|null */
 	private $parent = null;
 
 	/** @var PermissionAttachment[] */
diff --git a/src/pocketmine/permission/PermissionAttachment.php b/src/pocketmine/permission/PermissionAttachment.php
index 2eb059461..6f8520edf 100644
--- a/src/pocketmine/permission/PermissionAttachment.php
+++ b/src/pocketmine/permission/PermissionAttachment.php
@@ -27,7 +27,7 @@ use pocketmine\plugin\Plugin;
 use pocketmine\plugin\PluginException;
 
 class PermissionAttachment{
-	/** @var PermissionRemovedExecutor */
+	/** @var PermissionRemovedExecutor|null */
 	private $removed = null;
 
 	/** @var bool[] */
diff --git a/src/pocketmine/resourcepacks/ZippedResourcePack.php b/src/pocketmine/resourcepacks/ZippedResourcePack.php
index f0106573c..3a4ba556a 100644
--- a/src/pocketmine/resourcepacks/ZippedResourcePack.php
+++ b/src/pocketmine/resourcepacks/ZippedResourcePack.php
@@ -62,7 +62,7 @@ class ZippedResourcePack implements ResourcePack{
 	/** @var \stdClass */
 	protected $manifest;
 
-	/** @var string */
+	/** @var string|null */
 	protected $sha256 = null;
 
 	/** @var resource */
diff --git a/src/pocketmine/scheduler/AsyncTask.php b/src/pocketmine/scheduler/AsyncTask.php
index fd4fa0e93..dc4723c58 100644
--- a/src/pocketmine/scheduler/AsyncTask.php
+++ b/src/pocketmine/scheduler/AsyncTask.php
@@ -53,7 +53,7 @@ abstract class AsyncTask extends Collectable{
 	 */
 	private static $localObjectStorage;
 
-	/** @var AsyncWorker $worker */
+	/** @var AsyncWorker|null $worker */
 	public $worker = null;
 
 	/** @var \Threaded */
diff --git a/src/pocketmine/timings/TimingsHandler.php b/src/pocketmine/timings/TimingsHandler.php
index a7e54101b..5538c070f 100644
--- a/src/pocketmine/timings/TimingsHandler.php
+++ b/src/pocketmine/timings/TimingsHandler.php
@@ -136,7 +136,7 @@ class TimingsHandler{
 
 	/** @var string */
 	private $name;
-	/** @var TimingsHandler */
+	/** @var TimingsHandler|null */
 	private $parent = null;
 
 	/** @var int */