composer.json

@@ -1,8 +1,5 @@
 {
 	"name": "drupal/simple_message",
 	"description": "Displays a simple message.",
-	"type": "drupal-module",
+	"type": "drupal-module"
-	"require": {
-		"php": "^7.4"
-	}
 }

src/DisplaySimpleMessage.php

@@ -1,10 +1,7 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Drupal\simple_message;
 
-use Drupal\Core\Config\Config;
 use Drupal\Core\Routing\AdminContext;
 use Drupal\Core\Messenger\MessengerInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
@@ -17,9 +14,9 @@ final class DisplaySimpleMessage implements EventSubscriberInterface {
 
   use StringTranslationTrait;
 
-  private MessengerInterface $messenger;
+  private $messenger;
-  private AdminContext $adminContext;
+  private $adminContext;
-  private Config $config;
+  private $config;
 
   public function __construct(
     MessengerInterface $messenger,
@@ -31,7 +28,7 @@ final class DisplaySimpleMessage implements EventSubscriberInterface {
     $this->config = $configFactory->get('simple_message.config');
   }
 
-  public function displayMessage(GetResponseEvent $event): void {
+  public function displayMessage(GetResponseEvent $event) {
     if ($this->adminContext->isAdminRoute()) {
       return;
     }