diff --git a/src/pocketmine/command/Command.php b/src/pocketmine/command/Command.php
index 0e949f3f4..2f47e2029 100644
--- a/src/pocketmine/command/Command.php
+++ b/src/pocketmine/command/Command.php
@@ -26,6 +26,7 @@ declare(strict_types=1);
  */
 namespace pocketmine\command;
 
+use pocketmine\command\utils\CommandException;
 use pocketmine\lang\TextContainer;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\permission\PermissionManager;
@@ -92,6 +93,7 @@ abstract class Command{
 	 * @param string[]      $args
 	 *
 	 * @return mixed
+	 * @throws CommandException
 	 */
 	abstract public function execute(CommandSender $sender, string $commandLabel, array $args);
 
diff --git a/src/pocketmine/command/SimpleCommandMap.php b/src/pocketmine/command/SimpleCommandMap.php
index 88d95a5ba..d7296f82f 100644
--- a/src/pocketmine/command/SimpleCommandMap.php
+++ b/src/pocketmine/command/SimpleCommandMap.php
@@ -66,13 +66,13 @@ use pocketmine\command\defaults\VersionCommand;
 use pocketmine\command\defaults\WhitelistCommand;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\Server;
-use function array_map;
 use function array_shift;
 use function count;
 use function explode;
 use function implode;
 use function min;
-use function str_getcsv;
+use function preg_match_all;
+use function stripslashes;
 use function strpos;
 use function strtolower;
 use function trim;
@@ -247,7 +247,16 @@ class SimpleCommandMap implements CommandMap{
 	}
 
 	public function dispatch(CommandSender $sender, string $commandLine) : bool{
-		$args = array_map("\stripslashes", str_getcsv($commandLine, " "));
+		$args = [];
+		preg_match_all('/"((?:\\\\.|[^\\\\"])*)"|(\S+)/u', $commandLine, $matches);
+		foreach($matches[0] as $k => $_){
+			for($i = 1; $i <= 2; ++$i){
+				if($matches[$i][$k] !== ""){
+					$args[$k] = stripslashes($matches[$i][$k]);
+					break;
+				}
+			}
+		}
 		$sentCommandLabel = "";
 		$target = $this->matchCommand($sentCommandLabel, $args);
 
diff --git a/src/pocketmine/entity/Human.php b/src/pocketmine/entity/Human.php
index ee02412cb..d24b4f536 100644
--- a/src/pocketmine/entity/Human.php
+++ b/src/pocketmine/entity/Human.php
@@ -301,7 +301,7 @@ class Human extends Creature implements ProjectileSource, InventoryHolder{
 				$food = $this->getFood();
 				if($food > 0){
 					$food--;
-					$this->setFood($food);
+					$this->setFood(max($food, 0));
 				}
 			}
 		}
diff --git a/src/pocketmine/tile/Sign.php b/src/pocketmine/tile/Sign.php
index ca577ad93..39b3b550b 100644
--- a/src/pocketmine/tile/Sign.php
+++ b/src/pocketmine/tile/Sign.php
@@ -33,6 +33,8 @@ use function array_pad;
 use function array_slice;
 use function explode;
 use function implode;
+use function mb_check_encoding;
+use function mb_scrub;
 use function sprintf;
 
 class Sign extends Spawnable{
@@ -57,6 +59,9 @@ class Sign extends Spawnable{
 				}
 			}
 		}
+		$this->text = array_map(function(string $line) : string{
+			return mb_scrub($line, 'UTF-8');
+		}, $this->text);
 	}
 
 	protected function writeSaveData(CompoundTag $nbt) : void{
@@ -79,16 +84,16 @@ class Sign extends Spawnable{
 	 */
 	public function setText(?string $line1 = "", ?string $line2 = "", ?string $line3 = "", ?string $line4 = "") : void{
 		if($line1 !== null){
-			$this->text[0] = $line1;
+			$this->setLine(0, $line1, false);
 		}
 		if($line2 !== null){
-			$this->text[1] = $line2;
+			$this->setLine(1, $line2, false);
 		}
 		if($line3 !== null){
-			$this->text[2] = $line3;
+			$this->setLine(2, $line3, false);
 		}
 		if($line4 !== null){
-			$this->text[3] = $line4;
+			$this->setLine(3, $line4, false);
 		}
 
 		$this->onChanged();
@@ -103,6 +108,9 @@ class Sign extends Spawnable{
 		if($index < 0 or $index > 3){
 			throw new \InvalidArgumentException("Index must be in the range 0-3!");
 		}
+		if(!mb_check_encoding($line, 'UTF-8')){
+			throw new \InvalidArgumentException("Text must be valid UTF-8");
+		}
 
 		$this->text[$index] = $line;
 		if($update){
diff --git a/src/pocketmine/utils/TextFormat.php b/src/pocketmine/utils/TextFormat.php
index 40d236347..7d5b028ac 100644
--- a/src/pocketmine/utils/TextFormat.php
+++ b/src/pocketmine/utils/TextFormat.php
@@ -25,6 +25,7 @@ namespace pocketmine\utils;
 
 use function is_array;
 use function json_encode;
+use function mb_scrub;
 use function preg_quote;
 use function preg_replace;
 use function preg_split;
@@ -77,18 +78,19 @@ abstract class TextFormat{
 	}
 
 	/**
-	 * Cleans the string from Minecraft codes and ANSI Escape Codes
+	 * Cleans the string from Minecraft codes, ANSI Escape Codes and invalid UTF-8 characters
 	 *
 	 * @param string $string
 	 * @param bool   $removeFormat
 	 *
-	 * @return string
+	 * @return string valid clean UTF-8
 	 */
 	public static function clean(string $string, bool $removeFormat = true) : string{
+		$string = mb_scrub($string, 'UTF-8');
 		if($removeFormat){
-			return str_replace(TextFormat::ESCAPE, "", preg_replace(["/" . TextFormat::ESCAPE . "[0-9a-fk-or]/", "/\x1b[\\(\\][[0-9;\\[\\(]+[Bm]/"], "", $string));
+			return str_replace(TextFormat::ESCAPE, "", preg_replace(["/" . TextFormat::ESCAPE . "[0-9a-fk-or]/u", "/\x1b[\\(\\][[0-9;\\[\\(]+[Bm]/u"], "", $string));
 		}
-		return str_replace("\x1b", "", preg_replace("/\x1b[\\(\\][[0-9;\\[\\(]+[Bm]/", "", $string));
+		return str_replace("\x1b", "", preg_replace("/\x1b[\\(\\][[0-9;\\[\\(]+[Bm]/u", "", $string));
 	}
 
 	/**