diff --git a/src/pocketmine/network/AdvancedSourceInterface.php b/src/pocketmine/network/AdvancedSourceInterface.php
index 3e58140f2..2ba728c31 100644
--- a/src/pocketmine/network/AdvancedSourceInterface.php
+++ b/src/pocketmine/network/AdvancedSourceInterface.php
@@ -32,23 +32,23 @@ interface AdvancedSourceInterface extends SourceInterface{
 	 * @param string $address
 	 * @param int    $timeout Seconds
 	 */
-	public function blockAddress(string $address, int $timeout = 300);
+	public function blockAddress(string $address, int $timeout = 300) : void;
 
 	/**
 	 * @param string $address
 	 */
-	public function unblockAddress(string $address);
+	public function unblockAddress(string $address) : void;
 
 	/**
 	 * @param Network $network
 	 */
-	public function setNetwork(Network $network);
+	public function setNetwork(Network $network) : void;
 
 	/**
 	 * @param string $address
 	 * @param int    $port
 	 * @param string $payload
 	 */
-	public function sendRawPacket(string $address, int $port, string $payload);
+	public function sendRawPacket(string $address, int $port, string $payload) : void;
 
 }
diff --git a/src/pocketmine/network/CompressBatchedTask.php b/src/pocketmine/network/CompressBatchedTask.php
index 9ddd7baae..a8aa24a6b 100644
--- a/src/pocketmine/network/CompressBatchedTask.php
+++ b/src/pocketmine/network/CompressBatchedTask.php
@@ -43,7 +43,7 @@ class CompressBatchedTask extends AsyncTask{
 		$this->storeLocal($targets);
 	}
 
-	public function onRun(){
+	public function onRun() : void{
 		$batch = new BatchPacket();
 		$batch->payload = $this->data;
 		$this->data = null;
@@ -54,7 +54,7 @@ class CompressBatchedTask extends AsyncTask{
 		$this->setResult($batch->buffer, false);
 	}
 
-	public function onCompletion(Server $server){
+	public function onCompletion(Server $server) : void{
 		$pk = new BatchPacket($this->getResult());
 		$pk->isEncoded = true;
 
diff --git a/src/pocketmine/network/Network.php b/src/pocketmine/network/Network.php
index 6edb9977f..af907d77c 100644
--- a/src/pocketmine/network/Network.php
+++ b/src/pocketmine/network/Network.php
@@ -58,20 +58,20 @@ class Network{
 
 	}
 
-	public function addStatistics($upload, $download){
+	public function addStatistics(float $upload, float $download) : void{
 		$this->upload += $upload;
 		$this->download += $download;
 	}
 
-	public function getUpload(){
+	public function getUpload() : float{
 		return $this->upload;
 	}
 
-	public function getDownload(){
+	public function getDownload() : float{
 		return $this->download;
 	}
 
-	public function resetStatistics(){
+	public function resetStatistics() : void{
 		$this->upload = 0;
 		$this->download = 0;
 	}
@@ -83,7 +83,7 @@ class Network{
 		return $this->interfaces;
 	}
 
-	public function processInterfaces(){
+	public function processInterfaces() : void{
 		foreach($this->interfaces as $interface){
 			$this->processInterface($interface);
 		}
@@ -109,7 +109,7 @@ class Network{
 	/**
 	 * @param SourceInterface $interface
 	 */
-	public function registerInterface(SourceInterface $interface){
+	public function registerInterface(SourceInterface $interface) : void{
 		$this->server->getPluginManager()->callEvent($ev = new NetworkInterfaceRegisterEvent($interface));
 		if(!$ev->isCancelled()){
 			$interface->start();
@@ -125,7 +125,7 @@ class Network{
 	/**
 	 * @param SourceInterface $interface
 	 */
-	public function unregisterInterface(SourceInterface $interface){
+	public function unregisterInterface(SourceInterface $interface) : void{
 		$this->server->getPluginManager()->callEvent(new NetworkInterfaceUnregisterEvent($interface));
 		unset($this->interfaces[$hash = spl_object_hash($interface)], $this->advancedInterfaces[$hash]);
 	}
@@ -135,7 +135,7 @@ class Network{
 	 *
 	 * @param string $name
 	 */
-	public function setName(string $name){
+	public function setName(string $name) : void{
 		$this->name = $name;
 		foreach($this->interfaces as $interface){
 			$interface->setName($this->name);
@@ -149,7 +149,7 @@ class Network{
 		return $this->name;
 	}
 
-	public function updateName(){
+	public function updateName() : void{
 		foreach($this->interfaces as $interface){
 			$interface->setName($this->name);
 		}
@@ -167,7 +167,7 @@ class Network{
 	 * @param int    $port
 	 * @param string $payload
 	 */
-	public function sendPacket(string $address, int $port, string $payload){
+	public function sendPacket(string $address, int $port, string $payload) : void{
 		foreach($this->advancedInterfaces as $interface){
 			$interface->sendRawPacket($address, $port, $payload);
 		}
@@ -179,13 +179,13 @@ class Network{
 	 * @param string $address
 	 * @param int    $timeout
 	 */
-	public function blockAddress(string $address, int $timeout = 300){
+	public function blockAddress(string $address, int $timeout = 300) : void{
 		foreach($this->advancedInterfaces as $interface){
 			$interface->blockAddress($address, $timeout);
 		}
 	}
 
-	public function unblockAddress(string $address){
+	public function unblockAddress(string $address) : void{
 		foreach($this->advancedInterfaces as $interface){
 			$interface->unblockAddress($address);
 		}
diff --git a/src/pocketmine/network/SourceInterface.php b/src/pocketmine/network/SourceInterface.php
index e5a6b679a..e6676470c 100644
--- a/src/pocketmine/network/SourceInterface.php
+++ b/src/pocketmine/network/SourceInterface.php
@@ -37,7 +37,7 @@ interface SourceInterface{
 	/**
 	 * Performs actions needed to start the interface after it is registered.
 	 */
-	public function start();
+	public function start() : void;
 
 	/**
 	 * Sends a DataPacket to the interface, returns an unique identifier for the packet if $needACK is true
@@ -49,7 +49,7 @@ interface SourceInterface{
 	 *
 	 * @return int|null
 	 */
-	public function putPacket(Player $player, DataPacket $packet, bool $needACK = false, bool $immediate = true);
+	public function putPacket(Player $player, DataPacket $packet, bool $needACK = false, bool $immediate = true) : ?int;
 
 	/**
 	 * Terminates the connection
@@ -57,20 +57,20 @@ interface SourceInterface{
 	 * @param Player $player
 	 * @param string $reason
 	 */
-	public function close(Player $player, string $reason = "unknown reason");
+	public function close(Player $player, string $reason = "unknown reason") : void;
 
 	/**
 	 * @param string $name
 	 */
-	public function setName(string $name);
+	public function setName(string $name) : void;
 
 	/**
 	 * Called every tick to process events on the interface.
 	 */
 	public function process() : void;
 
-	public function shutdown();
+	public function shutdown() : void;
 
-	public function emergencyShutdown();
+	public function emergencyShutdown() : void;
 
 }
diff --git a/src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter.php b/src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter.php
index 385a64540..2f651a583 100644
--- a/src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter.php
+++ b/src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter.php
@@ -78,7 +78,7 @@ class PlayerNetworkSessionAdapter extends NetworkSession{
 		$this->player = $player;
 	}
 
-	public function handleDataPacket(DataPacket $packet){
+	public function handleDataPacket(DataPacket $packet) : void{
 		$timings = Timings::getReceiveDataPacketTimings($packet);
 		$timings->startTiming();
 
diff --git a/src/pocketmine/network/mcpe/RakLibInterface.php b/src/pocketmine/network/mcpe/RakLibInterface.php
index bd3998379..2f180ddf2 100644
--- a/src/pocketmine/network/mcpe/RakLibInterface.php
+++ b/src/pocketmine/network/mcpe/RakLibInterface.php
@@ -91,11 +91,11 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		$this->interface = new ServerHandler($this->rakLib, $this);
 	}
 
-	public function start(){
+	public function start() : void{
 		$this->rakLib->start(PTHREADS_INHERIT_CONSTANTS | PTHREADS_INHERIT_INI); //HACK: MainLogger needs INI and constants
 	}
 
-	public function setNetwork(Network $network){
+	public function setNetwork(Network $network) : void{
 		$this->network = $network;
 	}
 
@@ -117,7 +117,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		}
 	}
 
-	public function close(Player $player, string $reason = "unknown reason"){
+	public function close(Player $player, string $reason = "unknown reason") : void{
 		if(isset($this->identifiers[$h = spl_object_hash($player)])){
 			unset($this->players[$this->identifiers[$h]]);
 			unset($this->identifiersACK[$this->identifiers[$h]]);
@@ -126,12 +126,12 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		}
 	}
 
-	public function shutdown(){
+	public function shutdown() : void{
 		$this->server->getTickSleeper()->removeNotifier($this->sleeper);
 		$this->interface->shutdown();
 	}
 
-	public function emergencyShutdown(){
+	public function emergencyShutdown() : void{
 		$this->server->getTickSleeper()->removeNotifier($this->sleeper);
 		$this->interface->emergencyShutdown();
 	}
@@ -167,11 +167,11 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		}
 	}
 
-	public function blockAddress(string $address, int $timeout = 300){
+	public function blockAddress(string $address, int $timeout = 300) : void{
 		$this->interface->blockAddress($address, $timeout);
 	}
 
-	public function unblockAddress(string $address){
+	public function unblockAddress(string $address) : void{
 		$this->interface->unblockAddress($address);
 	}
 
@@ -179,7 +179,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		$this->server->handlePacket($this, $address, $port, $payload);
 	}
 
-	public function sendRawPacket(string $address, int $port, string $payload){
+	public function sendRawPacket(string $address, int $port, string $payload) : void{
 		$this->interface->sendRaw($address, $port, $payload);
 	}
 
@@ -187,7 +187,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 
 	}
 
-	public function setName(string $name){
+	public function setName(string $name) : void{
 		$info = $this->server->getQueryInformation();
 
 		$this->interface->sendOption("name", implode(";",
@@ -205,8 +205,8 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		);
 	}
 
-	public function setPortCheck($name){
-		$this->interface->sendOption("portChecking", (bool) $name);
+	public function setPortCheck(bool $name) : void{
+		$this->interface->sendOption("portChecking", $name);
 	}
 
 	public function handleOption(string $option, string $value) : void{
@@ -216,7 +216,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		}
 	}
 
-	public function putPacket(Player $player, DataPacket $packet, bool $needACK = false, bool $immediate = true){
+	public function putPacket(Player $player, DataPacket $packet, bool $needACK = false, bool $immediate = true) : ?int{
 		if(isset($this->identifiers[$h = spl_object_hash($player)])){
 			$identifier = $this->identifiers[$h];
 			if(!$packet->isEncoded){
diff --git a/src/pocketmine/network/mcpe/VerifyLoginTask.php b/src/pocketmine/network/mcpe/VerifyLoginTask.php
index cf4f5d374..a509e35ef 100644
--- a/src/pocketmine/network/mcpe/VerifyLoginTask.php
+++ b/src/pocketmine/network/mcpe/VerifyLoginTask.php
@@ -55,7 +55,7 @@ class VerifyLoginTask extends AsyncTask{
 		$this->packet = $packet;
 	}
 
-	public function onRun(){
+	public function onRun() : void{
 		$packet = $this->packet; //Get it in a local variable to make sure it stays unserialized
 
 		try{
@@ -142,7 +142,7 @@ class VerifyLoginTask extends AsyncTask{
 		$currentPublicKey = $claims["identityPublicKey"] ?? null; //if there are further links, the next link should be signed with this
 	}
 
-	public function onCompletion(Server $server){
+	public function onCompletion(Server $server) : void{
 		/** @var Player $player */
 		$player = $this->fetchLocal();
 		if($player->isClosed()){
diff --git a/src/pocketmine/network/query/QueryHandler.php b/src/pocketmine/network/query/QueryHandler.php
index 7c6770097..1f238962a 100644
--- a/src/pocketmine/network/query/QueryHandler.php
+++ b/src/pocketmine/network/query/QueryHandler.php
@@ -58,14 +58,14 @@ class QueryHandler{
 		$this->server->getLogger()->info($this->server->getLanguage()->translateString("pocketmine.server.query.running", [$addr, $port]));
 	}
 
-	public function regenerateInfo(){
+	public function regenerateInfo() : void{
 		$ev = $this->server->getQueryInformation();
 		$this->longData = $ev->getLongQuery();
 		$this->shortData = $ev->getShortQuery();
 		$this->timeout = microtime(true) + $ev->getTimeout();
 	}
 
-	public function regenerateToken(){
+	public function regenerateToken() : void{
 		$this->lastToken = $this->token;
 		$this->token = random_bytes(16);
 	}
@@ -74,7 +74,7 @@ class QueryHandler{
 		return Binary::readInt(substr(hash("sha512", $salt . ":" . $token, true), 7, 4));
 	}
 
-	public function handle(AdvancedSourceInterface $interface, string $address, int $port, string $packet){
+	public function handle(AdvancedSourceInterface $interface, string $address, int $port, string $packet) : void{
 		$offset = 2;
 		$packetType = ord($packet{$offset++});
 		$sessionID = Binary::readInt(substr($packet, $offset, 4));
diff --git a/src/pocketmine/network/rcon/RCON.php b/src/pocketmine/network/rcon/RCON.php
index 624045789..cf57cd106 100644
--- a/src/pocketmine/network/rcon/RCON.php
+++ b/src/pocketmine/network/rcon/RCON.php
@@ -82,7 +82,7 @@ class RCON{
 		$this->server->getLogger()->info("RCON running on $addr:$port");
 	}
 
-	public function stop(){
+	public function stop() : void{
 		$this->instance->close();
 		socket_write($this->ipcMainSocket, "\x00"); //make select() return
 		Server::microSleep(50000);
@@ -93,7 +93,7 @@ class RCON{
 		@socket_close($this->ipcThreadSocket);
 	}
 
-	public function check(){
+	public function check() : void{
 		$response = new RemoteConsoleCommandSender();
 		$command = $this->instance->cmd;
 
diff --git a/src/pocketmine/network/rcon/RCONInstance.php b/src/pocketmine/network/rcon/RCONInstance.php
index d1e98da2e..47790e4e6 100644
--- a/src/pocketmine/network/rcon/RCONInstance.php
+++ b/src/pocketmine/network/rcon/RCONInstance.php
@@ -102,11 +102,11 @@ class RCONInstance extends Thread{
 		return true;
 	}
 
-	public function close(){
+	public function close() : void{
 		$this->stop = true;
 	}
 
-	public function run(){
+	public function run() : void{
 		$this->registerClassLoader();
 
 		/** @var resource[] $clients */