diff --git a/README.md b/README.md
index 9fddbe9..d6e729c 100644
--- a/README.md
+++ b/README.md
@@ -86,7 +86,7 @@ class ExampleCommand extends Command
 {
     use WithoutOverlapping;
 
-    protected $mutexStrategy = 'mysql';
+    protected string $mutexStrategy = 'mysql';
 
     // ...
 }
@@ -125,7 +125,7 @@ class ExampleCommand extends Command
     use WithoutOverlapping;
 
     // In milliseconds
-    protected $mutexTimeout = 3000;
+    protected ?int $mutexTimeout = 3000;
 
     // ...
 }
diff --git a/src/Mutex.php b/src/Mutex.php
index 6060fe4..150535d 100644
--- a/src/Mutex.php
+++ b/src/Mutex.php
@@ -6,6 +6,7 @@
 use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\Redis as RedisFacade;
 use NinjaMutex\Lock\FlockLock;
+use NinjaMutex\Lock\LockAbstract;
 use NinjaMutex\Lock\MemcachedLock;
 use NinjaMutex\Lock\MySqlLock;
 use NinjaMutex\Lock\PhpRedisLock;
@@ -19,33 +20,25 @@ class Mutex
 {
     /**
      * The console command.
-     *
-     * @var \Illuminate\Console\Command
      */
-    private $command;
+    private Command $command;
 
     /**
      * The NinjaMutex.
-     *
-     * @var \NinjaMutex\Mutex
      */
-    private $ninjaMutex;
+    private NinjaMutex $ninjaMutex;
 
     /**
      * The NinjaMutex lock.
-     *
-     * @var \NinjaMutex\Lock\LockAbstract
      */
-    private $ninjaMutexLock;
+    private LockAbstract $ninjaMutexLock;
 
     /**
      * Create a new instance of the mutex.
-     *
-     * @param \Illuminate\Console\Command|\Illuminated\Console\WithoutOverlapping $command
-     * @return void
      */
     public function __construct(Command $command)
     {
+        /** @var WithoutOverlapping $command */
         $this->command = $command;
 
         $mutexName = $command->getMutexName();
@@ -55,10 +48,8 @@ public function __construct(Command $command)
 
     /**
      * Get the NinjaMutex lock.
-     *
-     * @return \NinjaMutex\Lock\LockAbstract
      */
-    public function getNinjaMutexLock()
+    public function getNinjaMutexLock(): LockAbstract
     {
         if (!empty($this->ninjaMutexLock)) {
             return $this->ninjaMutexLock;
@@ -88,11 +79,8 @@ public function getNinjaMutexLock()
 
     /**
      * Get the redis lock.
-     *
-     * @param string $client
-     * @return \NinjaMutex\Lock\LockAbstract
      */
-    private function getRedisLock($client)
+    private function getRedisLock(string $client): LockAbstract
     {
         $redis = RedisFacade::connection()->client();
 
@@ -103,12 +91,8 @@ private function getRedisLock($client)
 
     /**
      * Forward method calls to NinjaMutex.
-     *
-     * @param string $method
-     * @param mixed $parameters
-     * @return mixed
      */
-    public function __call($method, $parameters)
+    public function __call(string $method, mixed $parameters): mixed
     {
         return call_user_func_array([$this->ninjaMutex, $method], $parameters);
     }
diff --git a/src/WithoutOverlapping.php b/src/WithoutOverlapping.php
index 7606694..d72cb1d 100644
--- a/src/WithoutOverlapping.php
+++ b/src/WithoutOverlapping.php
@@ -9,12 +9,8 @@ trait WithoutOverlapping
 {
     /**
      * Overwrite the console command initialization.
-     *
-     * @param \Symfony\Component\Console\Input\InputInterface $input
-     * @param \Symfony\Component\Console\Output\OutputInterface $output
-     * @return void
      */
-    protected function initialize(InputInterface $input, OutputInterface $output)
+    protected function initialize(InputInterface $input, OutputInterface $output): void
     {
         $this->initializeMutex();
 
@@ -23,10 +19,8 @@ protected function initialize(InputInterface $input, OutputInterface $output)
 
     /**
      * Initialize the mutex.
-     *
-     * @return void
      */
-    protected function initializeMutex()
+    protected function initializeMutex(): void
     {
         $mutex = new Mutex($this);
 
@@ -42,10 +36,8 @@ protected function initializeMutex()
      * Get the mutex strategy.
      *
      * Currently supported: "file", "mysql", "redis" and "memcached".
-     *
-     * @return string
      */
-    public function getMutexStrategy()
+    public function getMutexStrategy(): string
     {
         return property_exists($this, 'mutexStrategy')
             ? $this->mutexStrategy
@@ -56,11 +48,8 @@ public function getMutexStrategy()
      * Set the mutex strategy.
      *
      * Currently supported: "file", "mysql", "redis" and "memcached".
-     *
-     * @param string $strategy
-     * @return void
      */
-    public function setMutexStrategy($strategy)
+    public function setMutexStrategy(string $strategy): void
     {
         $this->mutexStrategy = $strategy;
     }
@@ -72,10 +61,8 @@ public function setMutexStrategy($strategy)
      * `0` - check without waiting;
      * `{milliseconds}` - check, and wait for a maximum of milliseconds specified;
      * `null` - wait, till running command finish its execution;
-     *
-     * @return int|null
      */
-    public function getMutexTimeout()
+    public function getMutexTimeout(): int|null
     {
         return property_exists($this, 'mutexTimeout')
             ? $this->mutexTimeout
@@ -89,21 +76,16 @@ public function getMutexTimeout()
      * `0` - check without waiting;
      * `{milliseconds}` - check, and wait for a maximum of milliseconds specified;
      * `null` - wait, till running command finish its execution;
-     *
-     * @param int|null $timeout
-     * @return void
      */
-    public function setMutexTimeout($timeout)
+    public function setMutexTimeout(int|null $timeout): void
     {
         $this->mutexTimeout = $timeout;
     }
 
     /**
      * Get the mutex name.
-     *
-     * @return string
      */
-    public function getMutexName()
+    public function getMutexName(): string
     {
         $name = $this->getName();
         $argumentsHash = md5(json_encode($this->argument()));
@@ -113,10 +95,8 @@ public function getMutexName()
 
     /**
      * Get the mutex file storage path.
-     *
-     * @return string
      */
-    public function getMutexFileStorage()
+    public function getMutexFileStorage(): string
     {
         return storage_path('app');
     }
@@ -125,11 +105,8 @@ public function getMutexFileStorage()
      * Release the mutex lock.
      *
      * Called automatically, because it's registered as a shutdown function.
-     *
-     * @param \Illuminated\Console\Mutex $mutex
-     * @return void
      */
-    public function releaseMutexLock(Mutex $mutex)
+    public function releaseMutexLock(Mutex $mutex): void
     {
         $mutex->releaseLock();
     }
diff --git a/tests/MutexTest.php b/tests/MutexTest.php
index 62671b6..7924223 100644
--- a/tests/MutexTest.php
+++ b/tests/MutexTest.php
@@ -2,10 +2,12 @@
 
 namespace Illuminated\Console\Tests;
 
+use Illuminate\Console\Command;
 use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\Redis as RedisFacade;
 use Illuminated\Console\Mutex;
 use Illuminated\Console\Tests\App\Console\Commands\GenericCommand;
+use Mockery\Mock;
 use NinjaMutex\Lock\FlockLock;
 use NinjaMutex\Lock\MemcachedLock;
 use NinjaMutex\Lock\MySqlLock;
@@ -18,15 +20,11 @@ class MutexTest extends TestCase
 {
     /**
      * The console command mock.
-     *
-     * @var \Mockery\Mock|\Illuminate\Console\Command
      */
-    private $command;
+    private Mock|Command $command;
 
     /**
      * Setup the test environment.
-     *
-     * @return void
      */
     protected function setUp(): void
     {
diff --git a/tests/fixture/app/Console/Commands/GenericCommand.php b/tests/fixture/app/Console/Commands/GenericCommand.php
index 8ab3451..000b8f1 100644
--- a/tests/fixture/app/Console/Commands/GenericCommand.php
+++ b/tests/fixture/app/Console/Commands/GenericCommand.php
@@ -18,10 +18,8 @@ class GenericCommand extends Command
 
     /**
      * Handle the command.
-     *
-     * @return void
      */
-    public function handle()
+    public function handle(): void
     {
         $this->info('Done!');
     }
diff --git a/tests/fixture/app/Console/Commands/MysqlStrategyCommand.php b/tests/fixture/app/Console/Commands/MysqlStrategyCommand.php
index 51de935..8e9bc9b 100644
--- a/tests/fixture/app/Console/Commands/MysqlStrategyCommand.php
+++ b/tests/fixture/app/Console/Commands/MysqlStrategyCommand.php
@@ -18,17 +18,13 @@ class MysqlStrategyCommand extends Command
 
     /**
      * The mutex strategy.
-     *
-     * @var string
      */
-    protected $mutexStrategy = 'mysql';
+    protected string $mutexStrategy = 'mysql';
 
     /**
      * Handle the command.
-     *
-     * @return void
      */
-    public function handle()
+    public function handle(): void
     {
         $this->info('Done!');
     }
diff --git a/tests/fixture/app/Console/Commands/NullTimeoutCommand.php b/tests/fixture/app/Console/Commands/NullTimeoutCommand.php
index 9427542..ece8f3a 100644
--- a/tests/fixture/app/Console/Commands/NullTimeoutCommand.php
+++ b/tests/fixture/app/Console/Commands/NullTimeoutCommand.php
@@ -18,17 +18,13 @@ class NullTimeoutCommand extends Command
 
     /**
      * The mutex timeout.
-     *
-     * @var int|null
      */
-    protected $mutexTimeout;
+    protected ?int $mutexTimeout = null;
 
     /**
      * Handle the command.
-     *
-     * @return void
      */
-    public function handle()
+    public function handle(): void
     {
         $this->info('Done!');
     }
diff --git a/tests/fixture/app/Console/Commands/TimeoutCommand.php b/tests/fixture/app/Console/Commands/TimeoutCommand.php
index ccc43b6..9d9833c 100644
--- a/tests/fixture/app/Console/Commands/TimeoutCommand.php
+++ b/tests/fixture/app/Console/Commands/TimeoutCommand.php
@@ -18,17 +18,13 @@ class TimeoutCommand extends Command
 
     /**
      * The mutex timeout.
-     *
-     * @var int|null
      */
-    protected $mutexTimeout = 3000;
+    protected ?int $mutexTimeout = 3000;
 
     /**
      * Handle the command.
-     *
-     * @return void
      */
-    public function handle()
+    public function handle(): void
     {
         $this->info('Done!');
     }