diff --git a/Debug/WrappedListener.php b/Debug/WrappedListener.php
index e047639..9b910e6 100644
--- a/Debug/WrappedListener.php
+++ b/Debug/WrappedListener.php
@@ -52,7 +52,7 @@ public function __construct($listener, ?string $name, Stopwatch $stopwatch, Even
             $this->pretty = $this->name.'::'.$listener[1];
         } elseif ($listener instanceof \Closure) {
             $r = new \ReflectionFunction($listener);
-            if (false !== strpos($r->name, '{closure}')) {
+            if (str_contains($r->name, '{closure}')) {
                 $this->pretty = $this->name = 'closure';
             } elseif ($class = $r->getClosureScopeClass()) {
                 $this->name = $class->name;
diff --git a/composer.json b/composer.json
index 0a518a5..55c2716 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,8 @@
     ],
     "require": {
         "php": ">=7.1.3",
-        "symfony/event-dispatcher-contracts": "^1.1"
+        "symfony/event-dispatcher-contracts": "^1.1",
+        "symfony/polyfill-php80": "^1.16"
     },
     "require-dev": {
         "symfony/dependency-injection": "^3.4|^4.0|^5.0",