diff --git a/composer.lock b/composer.lock
index 6bfe05bd3..1786fc4ad 100644
--- a/composer.lock
+++ b/composer.lock
@@ -636,16 +636,16 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "0.12.11",
+            "version": "0.12.14",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "ca5f2b7cf81c6d8fba74f9576970399c5817e03b"
+                "reference": "37bdd26a80235d0f9045b49f4151102b7831cbe2"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/ca5f2b7cf81c6d8fba74f9576970399c5817e03b",
-                "reference": "ca5f2b7cf81c6d8fba74f9576970399c5817e03b",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/37bdd26a80235d0f9045b49f4151102b7831cbe2",
+                "reference": "37bdd26a80235d0f9045b49f4151102b7831cbe2",
                 "shasum": ""
             },
             "require": {
@@ -671,7 +671,7 @@
                 "MIT"
             ],
             "description": "PHPStan - PHP Static Analysis Tool",
-            "time": "2020-02-16T14:00:29+00:00"
+            "time": "2020-03-02T22:29:43+00:00"
         },
         {
             "name": "phpstan/phpstan-phpunit",
diff --git a/src/CoreConstants.php b/src/CoreConstants.php
index b67745e04..bf88306f1 100644
--- a/src/CoreConstants.php
+++ b/src/CoreConstants.php
@@ -23,6 +23,10 @@ declare(strict_types=1);
 
 namespace pocketmine;
 
+use function define;
+use function defined;
+use function dirname;
+
 // composer autoload doesn't use require_once and also pthreads can inherit things
 if(defined('pocketmine\_CORE_CONSTANTS_INCLUDED')){
 	return;
diff --git a/src/GlobalConstants.php b/src/GlobalConstants.php
index d3b4a9f9a..e32d07c04 100644
--- a/src/GlobalConstants.php
+++ b/src/GlobalConstants.php
@@ -19,6 +19,8 @@
  *
 */
 
+declare(strict_types=1);
+
 // composer autoload doesn't use require_once and also pthreads can inherit things
 if(defined('pocketmine\_GLOBAL_CONSTANTS_INCLUDED')){
 	return;
diff --git a/src/VersionInfo.php b/src/VersionInfo.php
index 20e7272b8..4a8f59fb7 100644
--- a/src/VersionInfo.php
+++ b/src/VersionInfo.php
@@ -23,6 +23,8 @@ declare(strict_types=1);
 
 namespace pocketmine;
 
+use function defined;
+
 // composer autoload doesn't use require_once and also pthreads can inherit things
 // TODO: drop this file and use a final class with constants
 if(defined('pocketmine\_VERSION_INFO_INCLUDED')){
diff --git a/src/entity/effect/Effect.php b/src/entity/effect/Effect.php
index bcc347cf6..8b6e757e1 100644
--- a/src/entity/effect/Effect.php
+++ b/src/entity/effect/Effect.php
@@ -43,7 +43,7 @@ class Effect{
 	/**
 	 * @param int    $id Effect ID as per Minecraft PE
 	 * @param string $name Translation key used for effect name
-	 * @param Color  $color
+	 * @param Color  $color Color of bubbles given by this effect
 	 * @param bool   $isBad Whether the effect is harmful
 	 * @param bool   $hasBubbles Whether the effect has potion bubbles. Some do not (e.g. Instant Damage has its own particles instead of bubbles)
 	 */
diff --git a/src/entity/object/ExperienceOrb.php b/src/entity/object/ExperienceOrb.php
index a1059ca94..c87217795 100644
--- a/src/entity/object/ExperienceOrb.php
+++ b/src/entity/object/ExperienceOrb.php
@@ -39,14 +39,10 @@ class ExperienceOrb extends Entity{
 	public const TAG_VALUE_PC = "Value"; //short
 	public const TAG_VALUE_PE = "experience value"; //int (WTF?)
 
-	/**
-	 * Max distance an orb will follow a player across.
-	 */
+	/** Max distance an orb will follow a player across. */
 	public const MAX_TARGET_DISTANCE = 8.0;
 
-	/**
-	 * Split sizes used for dropping experience orbs.
-	 */
+	/** Split sizes used for dropping experience orbs. */
 	public const ORB_SPLIT_SIZES = [2477, 1237, 617, 307, 149, 73, 37, 17, 7, 3, 1]; //This is indexed biggest to smallest so that we can return as soon as we found the biggest value.
 
 	/**
diff --git a/src/network/mcpe/protocol/AvailableCommandsPacket.php b/src/network/mcpe/protocol/AvailableCommandsPacket.php
index d98ee2e01..70992f42a 100644
--- a/src/network/mcpe/protocol/AvailableCommandsPacket.php
+++ b/src/network/mcpe/protocol/AvailableCommandsPacket.php
@@ -77,9 +77,7 @@ class AvailableCommandsPacket extends DataPacket implements ClientboundPacket{
 	 */
 	public const ARG_FLAG_ENUM = 0x200000;
 
-	/**
-	 * This is used for /xp <level: int>L. It can only be applied to integer parameters.
-	 */
+	/** This is used for /xp <level: int>L. It can only be applied to integer parameters. */
 	public const ARG_FLAG_POSTFIX = 0x1000000;
 
 	public const HARDCODED_ENUM_NAMES = [
diff --git a/src/network/mcpe/protocol/ProtocolInfo.php b/src/network/mcpe/protocol/ProtocolInfo.php
index 8a120d142..f6541eef3 100644
--- a/src/network/mcpe/protocol/ProtocolInfo.php
+++ b/src/network/mcpe/protocol/ProtocolInfo.php
@@ -40,17 +40,11 @@ final class ProtocolInfo{
 	 * This file is generated automatically, do not edit it manually.
 	 */
 
-	/**
-	 * Actual Minecraft: PE protocol version
-	 */
+	/** Actual Minecraft: PE protocol version */
 	public const CURRENT_PROTOCOL = 389;
-	/**
-	 * Current Minecraft PE version reported by the server. This is usually the earliest currently supported version.
-	 */
+	/** Current Minecraft PE version reported by the server. This is usually the earliest currently supported version. */
 	public const MINECRAFT_VERSION = 'v1.14.0';
-	/**
-	 * Version number sent to clients in ping responses.
-	 */
+	/** Version number sent to clients in ping responses. */
 	public const MINECRAFT_VERSION_NETWORK = '1.14.0';
 
 	public const LOGIN_PACKET = 0x01;
diff --git a/src/player/Player.php b/src/player/Player.php
index 3a2e8fce1..71d3402fd 100644
--- a/src/player/Player.php
+++ b/src/player/Player.php
@@ -1601,7 +1601,7 @@ class Player extends Human implements CommandSender, ChunkLoader, ChunkListener,
 			$item = $this->inventory->getItemInHand();
 			$oldItem = clone $item;
 			if($this->getWorld()->useBreakOn($pos, $item, $this, true)){
-				if($this->hasFiniteResources() and !$item->equalsExact($oldItem)){
+				if($this->hasFiniteResources() and !$item->equalsExact($oldItem) and $oldItem->equalsExact($this->inventory->getItemInHand())){
 					$this->inventory->setItemInHand($item);
 				}
 				$this->hungerManager->exhaust(0.025, PlayerExhaustEvent::CAUSE_MINING);
@@ -1625,7 +1625,7 @@ class Player extends Human implements CommandSender, ChunkLoader, ChunkListener,
 			$item = $this->inventory->getItemInHand(); //this is a copy of the real item
 			$oldItem = clone $item;
 			if($this->getWorld()->useItemOn($pos, $item, $face, $clickOffset, $this, true)){
-				if($this->hasFiniteResources() and !$item->equalsExact($oldItem)){
+				if($this->hasFiniteResources() and !$item->equalsExact($oldItem) and $oldItem->equalsExact($this->inventory->getItemInHand())){
 					$this->inventory->setItemInHand($item);
 				}
 				return true;
@@ -1694,7 +1694,7 @@ class Player extends Human implements CommandSender, ChunkLoader, ChunkListener,
 		if($this->isAlive()){
 			//reactive damage like thorns might cause us to be killed by attacking another mob, which
 			//would mean we'd already have dropped the inventory by the time we reached here
-			if($heldItem->onAttackEntity($entity) and $this->hasFiniteResources()){ //always fire the hook, even if we are survival
+			if($heldItem->onAttackEntity($entity) and $this->hasFiniteResources() and $heldItem->equalsExact($this->inventory->getItemInHand())){ //always fire the hook, even if we are survival
 				$this->inventory->setItemInHand($heldItem);
 			}
 
diff --git a/src/plugin/PluginDescription.php b/src/plugin/PluginDescription.php
index c4d1d3f05..dd7a06835 100644
--- a/src/plugin/PluginDescription.php
+++ b/src/plugin/PluginDescription.php
@@ -53,6 +53,8 @@ class PluginDescription{
 	private $api;
 	/** @var int[] */
 	private $compatibleMcpeProtocols = [];
+	/** @var string[] */
+	private $compatibleOperatingSystems = [];
 	/**
 	 * @var string[][]
 	 * @phpstan-var array<string, list<mixed>>
@@ -112,6 +114,7 @@ class PluginDescription{
 
 		$this->api = array_map("\strval", (array) ($plugin["api"] ?? []));
 		$this->compatibleMcpeProtocols = array_map("\intval", (array) ($plugin["mcpe-protocol"] ?? []));
+		$this->compatibleOperatingSystems = array_map("\strval", (array) ($plugin["os"] ?? []));
 
 		if(isset($plugin["commands"]) and is_array($plugin["commands"])){
 			$this->commands = $plugin["commands"];
@@ -185,6 +188,13 @@ class PluginDescription{
 		return $this->compatibleMcpeProtocols;
 	}
 
+	/**
+	 * @return string[]
+	 */
+	public function getCompatibleOperatingSystems() : array{
+		return $this->compatibleOperatingSystems;
+	}
+
 	/**
 	 * @return string[]
 	 */
diff --git a/src/plugin/PluginManager.php b/src/plugin/PluginManager.php
index 5e031b741..ced8032b6 100644
--- a/src/plugin/PluginManager.php
+++ b/src/plugin/PluginManager.php
@@ -46,6 +46,7 @@ use function explode;
 use function file_exists;
 use function get_class;
 use function implode;
+use function in_array;
 use function is_a;
 use function is_array;
 use function is_dir;
@@ -251,6 +252,14 @@ class PluginManager{
 					continue;
 				}
 
+				if(count($description->getCompatibleOperatingSystems()) > 0 and !in_array(Utils::getOS(), $description->getCompatibleOperatingSystems(), true)) {
+					$this->server->getLogger()->error($this->server->getLanguage()->translateString("pocketmine.plugin.loadError", [
+						$name,
+						$this->server->getLanguage()->translateString("%pocketmine.plugin.incompatibleOS", [implode(", ", $description->getCompatibleOperatingSystems())])
+					]));
+					continue;
+				}
+
 				if(count($pluginMcpeProtocols = $description->getCompatibleMcpeProtocols()) > 0){
 					$serverMcpeProtocols = [ProtocolInfo::CURRENT_PROTOCOL];
 					if(count(array_intersect($pluginMcpeProtocols, $serverMcpeProtocols)) === 0){
diff --git a/src/thread/Thread.php b/src/thread/Thread.php
index aec708e23..26c2037b2 100644
--- a/src/thread/Thread.php
+++ b/src/thread/Thread.php
@@ -22,6 +22,7 @@
 declare(strict_types=1);
 
 namespace pocketmine\thread;
+use const PTHREADS_INHERIT_ALL;
 
 /**
  * This class must be extended by all custom threading classes
@@ -29,7 +30,7 @@ namespace pocketmine\thread;
 abstract class Thread extends \Thread{
 	use CommonThreadPartsTrait;
 
-	public function start(?int $options = \PTHREADS_INHERIT_ALL) : bool{
+	public function start(?int $options = PTHREADS_INHERIT_ALL) : bool{
 		//this is intentionally not traitified
 		ThreadManager::getInstance()->add($this);
 
diff --git a/src/thread/Worker.php b/src/thread/Worker.php
index 75b106a82..1d473e95f 100644
--- a/src/thread/Worker.php
+++ b/src/thread/Worker.php
@@ -22,6 +22,7 @@
 declare(strict_types=1);
 
 namespace pocketmine\thread;
+use const PTHREADS_INHERIT_ALL;
 
 /**
  * This class must be extended by all custom threading classes
@@ -29,7 +30,7 @@ namespace pocketmine\thread;
 abstract class Worker extends \Worker{
 	use CommonThreadPartsTrait;
 
-	public function start(?int $options = \PTHREADS_INHERIT_ALL) : bool{
+	public function start(?int $options = PTHREADS_INHERIT_ALL) : bool{
 		//this is intentionally not traitified
 		ThreadManager::getInstance()->add($this);
 
diff --git a/src/world/format/Chunk.php b/src/world/format/Chunk.php
index 82aa8bde2..c1ab0db60 100644
--- a/src/world/format/Chunk.php
+++ b/src/world/format/Chunk.php
@@ -159,7 +159,7 @@ class Chunk{
 	 * Returns the internal ID of the blockstate at the given coordinates.
 	 *
 	 * @param int $x 0-15
-	 * @param int $y
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 *
 	 * @return int bitmap, (id << 4) | meta
@@ -180,7 +180,7 @@ class Chunk{
 	 * Returns the sky light level at the specified chunk block coordinates
 	 *
 	 * @param int $x 0-15
-	 * @param int $y
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 *
 	 * @return int 0-15
@@ -193,7 +193,7 @@ class Chunk{
 	 * Sets the sky light level at the specified chunk block coordinates
 	 *
 	 * @param int $x 0-15
-	 * @param int $y
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 * @param int $level 0-15
 	 */
@@ -211,7 +211,7 @@ class Chunk{
 	 * Returns the block light level at the specified chunk block coordinates
 	 *
 	 * @param int $x 0-15
-	 * @param int $y 0-15
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 *
 	 * @return int 0-15
@@ -224,7 +224,7 @@ class Chunk{
 	 * Sets the block light level at the specified chunk block coordinates
 	 *
 	 * @param int $x 0-15
-	 * @param int $y 0-15
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 * @param int $level 0-15
 	 */
@@ -452,7 +452,7 @@ class Chunk{
 	 * Returns the tile at the specified chunk block coordinates, or null if no tile exists.
 	 *
 	 * @param int $x 0-15
-	 * @param int $y
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 */
 	public function getTile(int $x, int $y, int $z) : ?Tile{
@@ -630,7 +630,7 @@ class Chunk{
 	 * Hashes the given chunk block coordinates into a single integer.
 	 *
 	 * @param int $x 0-15
-	 * @param int $y
+	 * @param int $y 0-255
 	 * @param int $z 0-15
 	 */
 	public static function blockHash(int $x, int $y, int $z) : int{