diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 99c9e32..a84bd54 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,7 +5,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: ['ubuntu-latest']
-                php-versions: ['7.4', '8.0', '8.1']
+                php-versions: ['8.0', '8.1']
         runs-on: ${{ matrix.operating-system }}
         steps:
             -   name: Checkout
diff --git a/composer.json b/composer.json
index 40b6d93..d64d70b 100644
--- a/composer.json
+++ b/composer.json
@@ -10,18 +10,18 @@
         }
     ],
     "require": {
-        "php":  ">=7.4",
-        "psr/container": "^1.0"
+        "php":  "~8.0 || ~8.1",
+        "psr/container": "^1.0 || ^2.0.1"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.4.2",
-        "phpstan/phpstan": "^0.12.52",
-        "phpstan/phpstan-phpunit": "^0.12.16",
+        "phpstan/phpstan": "^1.0.2",
+        "phpstan/phpstan-phpunit": "^1.0.0",
         "phpstan/extension-installer": "^1.0.5",
-        "squizlabs/php_codesniffer": "^3.5.8",
-        "doctrine/coding-standard": "^8.2",
+        "squizlabs/php_codesniffer": "^3.6.1",
+        "doctrine/coding-standard": "^9.0",
         "roave/security-advisories": "dev-latest",
-        "league/container": "^3.3.3"
+        "league/container": "^4.1.2"
     },
     "autoload": {
         "psr-4": {
diff --git a/examples/2-intermediate-create-middleware.php b/examples/2-intermediate-create-middleware.php
index 35e9489..b072d11 100644
--- a/examples/2-intermediate-create-middleware.php
+++ b/examples/2-intermediate-create-middleware.php
@@ -29,14 +29,14 @@ public function log($info) { echo "LOG: $info\n"; }
 // use it later.
 class LoggingMiddleware implements Middleware
 {
-    protected $logger;
+    protected Logger $logger;
 
     public function __construct(Logger $logger)
     {
         $this->logger = $logger;
     }
 
-    public function execute($command, callable $next)
+    public function execute(object $command, callable $next): mixed
     {
         $commandClass = \get_class($command);
 
@@ -62,7 +62,7 @@ public function execute($command, callable $next)
 // in the previous example, otherwise our commands won't be executed!
 $commandBus = new CommandBus(
     new LoggingMiddleware(new Logger()),
-    $handlerMiddleware
+    $handlerMiddleware,
 );
 
 // Controller Code
diff --git a/examples/4-conditional-handlers.php b/examples/4-conditional-handlers.php
index 0746ee6..cbf733c 100644
--- a/examples/4-conditional-handlers.php
+++ b/examples/4-conditional-handlers.php
@@ -31,7 +31,7 @@ public function __construct(CommandBus $commandBus)
         $this->commandBus = $commandBus;
     }
 
-    public function execute($command, callable $next)
+    public function execute(object $command, callable $next): mixed
     {
         if ($command instanceof ExternalCommand) {
             return $this->commandBus->handle($command);
@@ -43,9 +43,11 @@ public function execute($command, callable $next)
 // and we'll create a custom command handler/middleware
 final class ExternalCommandHandler implements Middleware
 {
-    public function execute($command, callable $next)
+    public function execute(object $command, callable $next): mixed
     {
         echo \sprintf("Dispatched %s!\n", \get_class($command));
+
+        return null;
     }
 }
 
diff --git a/src/CommandBus.php b/src/CommandBus.php
index 40c9057..63a61e2 100644
--- a/src/CommandBus.php
+++ b/src/CommandBus.php
@@ -23,10 +23,8 @@ public function __construct(Middleware ...$middleware)
 
     /**
      * Executes the given command and optionally returns a value
-     *
-     * @return mixed
      */
-    public function handle(object $command)
+    public function handle(object $command): mixed
     {
         return ($this->middlewareChain)($command);
     }
@@ -39,7 +37,7 @@ private function createExecutionChain(array $middlewareList): Closure
         $lastCallable = static fn () => null;
 
         while ($middleware = array_pop($middlewareList)) {
-            $lastCallable = static fn (object $command) => $middleware->execute($command, $lastCallable);
+            $lastCallable = static fn (object $command): mixed => $middleware->execute($command, $lastCallable);
         }
 
         return $lastCallable;
diff --git a/src/Handler/CommandHandlerMiddleware.php b/src/Handler/CommandHandlerMiddleware.php
index ddf637e..1674e2d 100644
--- a/src/Handler/CommandHandlerMiddleware.php
+++ b/src/Handler/CommandHandlerMiddleware.php
@@ -8,8 +8,6 @@
 use League\Tactician\Middleware;
 use Psr\Container\ContainerInterface;
 
-use function get_class;
-
 /**
  * Our basic middleware for executing commands.
  *
@@ -17,24 +15,17 @@
  */
 final class CommandHandlerMiddleware implements Middleware
 {
-    private ContainerInterface $container;
-    private CommandToHandlerMapping $mapping;
-
-    public function __construct(ContainerInterface $container, CommandToHandlerMapping $mapping)
+    public function __construct(private ContainerInterface $container, private CommandToHandlerMapping $mapping)
     {
-        $this->container = $container;
-        $this->mapping   = $mapping;
     }
 
     /**
      * Executes a command and optionally returns a value
-     *
-     * @return mixed
      */
-    public function execute(object $command, callable $next)
+    public function execute(object $command, callable $next): mixed
     {
         // 1. Based on the command we received, get the Handler method to call.
-        $methodToCall = $this->mapping->findHandlerForCommand(get_class($command));
+        $methodToCall = $this->mapping->findHandlerForCommand($command::class);
 
         // 2.  Retrieve an instance of the Handler from our PSR-11 container
         //     This assumes the container id is the same as the class name but
diff --git a/src/Handler/Mapping/MapByNamingConvention/ClassName/Suffix.php b/src/Handler/Mapping/MapByNamingConvention/ClassName/Suffix.php
index b282bb5..39d92fe 100644
--- a/src/Handler/Mapping/MapByNamingConvention/ClassName/Suffix.php
+++ b/src/Handler/Mapping/MapByNamingConvention/ClassName/Suffix.php
@@ -6,11 +6,8 @@
 
 final class Suffix implements ClassNameInflector
 {
-    private string $suffix;
-
-    public function __construct(string $suffix)
+    public function __construct(private string $suffix)
     {
-        $this->suffix = $suffix;
     }
 
     public function getClassName(string $commandClassName): string
diff --git a/src/Handler/Mapping/MapByNamingConvention/MapByNamingConvention.php b/src/Handler/Mapping/MapByNamingConvention/MapByNamingConvention.php
index 315a901..9e12844 100644
--- a/src/Handler/Mapping/MapByNamingConvention/MapByNamingConvention.php
+++ b/src/Handler/Mapping/MapByNamingConvention/MapByNamingConvention.php
@@ -15,14 +15,10 @@
  */
 final class MapByNamingConvention implements CommandToHandlerMapping
 {
-    private ClassNameInflector $classNameInflector;
-
-    private MethodNameInflector $methodNameInflector;
-
-    public function __construct(ClassNameInflector $classNameInflector, MethodNameInflector $methodNameInflector)
-    {
-        $this->classNameInflector  = $classNameInflector;
-        $this->methodNameInflector = $methodNameInflector;
+    public function __construct(
+        private ClassNameInflector $classNameInflector,
+        private MethodNameInflector $methodNameInflector,
+    ) {
     }
 
     public function findHandlerForCommand(string $commandFQCN): MethodToCall
diff --git a/src/Handler/Mapping/MapByNamingConvention/MethodName/HandleClassNameWithoutSuffix.php b/src/Handler/Mapping/MapByNamingConvention/MethodName/HandleClassNameWithoutSuffix.php
index 100ea04..b0e3214 100644
--- a/src/Handler/Mapping/MapByNamingConvention/MethodName/HandleClassNameWithoutSuffix.php
+++ b/src/Handler/Mapping/MapByNamingConvention/MethodName/HandleClassNameWithoutSuffix.php
@@ -21,17 +21,14 @@
  */
 final class HandleClassNameWithoutSuffix implements MethodNameInflector
 {
-    private string $suffix;
-
     private int $suffixLength;
     private HandleLastPartOfClassName $handleLastPartOfClassName;
 
     /**
      * @param string $suffix The string to remove from end of each class name
      */
-    public function __construct(string $suffix = 'Command')
+    public function __construct(private string $suffix = 'Command')
     {
-        $this->suffix                    = $suffix;
         $this->suffixLength              = strlen($suffix);
         $this->handleLastPartOfClassName = new HandleLastPartOfClassName();
     }
diff --git a/src/Handler/Mapping/MapByNamingConvention/MethodName/LastPartOfClassName.php b/src/Handler/Mapping/MapByNamingConvention/MethodName/LastPartOfClassName.php
index d9f7147..7617652 100644
--- a/src/Handler/Mapping/MapByNamingConvention/MethodName/LastPartOfClassName.php
+++ b/src/Handler/Mapping/MapByNamingConvention/MethodName/LastPartOfClassName.php
@@ -4,7 +4,7 @@
 
 namespace League\Tactician\Handler\Mapping\MapByNamingConvention\MethodName;
 
-use function strpos;
+use function str_contains;
 use function strrpos;
 use function strtolower;
 use function substr;
@@ -21,7 +21,7 @@ final class LastPartOfClassName implements MethodNameInflector
     public function getMethodName(string $commandClassNameName): string
     {
         // If class name has a namespace separator, only take last portion
-        if (strpos($commandClassNameName, '\\') !== false) {
+        if (str_contains($commandClassNameName, '\\')) {
             $commandClassNameName = substr($commandClassNameName, strrpos($commandClassNameName, '\\') + 1);
         }
 
diff --git a/src/Handler/Mapping/MapByStaticList/MapByStaticList.php b/src/Handler/Mapping/MapByStaticList/MapByStaticList.php
index 92caee7..643cf31 100644
--- a/src/Handler/Mapping/MapByStaticList/MapByStaticList.php
+++ b/src/Handler/Mapping/MapByStaticList/MapByStaticList.php
@@ -24,13 +24,9 @@
  */
 final class MapByStaticList implements CommandToHandlerMapping
 {
-    /** @var array<string, array<string>> */
-    private array $mapping;
-
     /** @param array<string, array<string>> $mapping */
-    public function __construct(array $mapping)
+    public function __construct(private array $mapping)
     {
-        $this->mapping = $mapping;
     }
 
     public function findHandlerForCommand(string $commandFQCN): MethodToCall
diff --git a/src/Handler/Mapping/MethodDoesNotExist.php b/src/Handler/Mapping/MethodDoesNotExist.php
index 76a5ec9..d86f8de 100644
--- a/src/Handler/Mapping/MethodDoesNotExist.php
+++ b/src/Handler/Mapping/MethodDoesNotExist.php
@@ -15,10 +15,6 @@
  */
 final class MethodDoesNotExist extends BadMethodCallException implements Exception
 {
-    private string $className;
-
-    private string $methodName;
-
     public static function on(string $className, string $methodName): self
     {
         return new self(
@@ -39,10 +35,8 @@ public function getMethodName(): string
         return $this->methodName;
     }
 
-    private function __construct(string $message, string $className, string $methodName)
+    private function __construct(string $message, private string $className, private string $methodName)
     {
         parent::__construct($message);
-        $this->className  = $className;
-        $this->methodName = $methodName;
     }
 }
diff --git a/src/Handler/Mapping/MethodToCall.php b/src/Handler/Mapping/MethodToCall.php
index 2229b73..c07a3df 100644
--- a/src/Handler/Mapping/MethodToCall.php
+++ b/src/Handler/Mapping/MethodToCall.php
@@ -8,11 +8,7 @@
 
 final class MethodToCall
 {
-    private string $className;
-
-    private string $methodName;
-
-    public function __construct(string $className, string $methodName)
+    public function __construct(private string $className, private string $methodName)
     {
         // If the method does not actually exist, we'll also check if __call exists (mainly for
         // legacy purposes). That said, we won't rewrite the method name to __call because our
@@ -20,9 +16,6 @@ public function __construct(string $className, string $methodName)
         if (! method_exists($className, $methodName) && ! method_exists($className, '__call')) {
             throw MethodDoesNotExist::on($className, $methodName);
         }
-
-        $this->className  = $className;
-        $this->methodName = $methodName;
     }
 
     public function getClassName(): string
diff --git a/src/Middleware.php b/src/Middleware.php
index bb57950..35be7b5 100644
--- a/src/Middleware.php
+++ b/src/Middleware.php
@@ -16,8 +16,5 @@
  */
 interface Middleware
 {
-    /**
-     * @return mixed
-     */
-    public function execute(object $command, callable $next);
+    public function execute(object $command, callable $next): mixed;
 }