diff --git a/Client.php b/Client.php
index f0dd66ece8..5c9169ce4b 100644
--- a/Client.php
+++ b/Client.php
@@ -85,7 +85,7 @@ protected function getScript($request)
 
         $requires = '';
         foreach (get_declared_classes() as $class) {
-            if (0 === strpos($class, 'ComposerAutoloaderInit')) {
+            if (str_starts_with($class, 'ComposerAutoloaderInit')) {
                 $r = new \ReflectionClass($class);
                 $file = \dirname($r->getFileName(), 2).'/autoload.php';
                 if (file_exists($file)) {
diff --git a/Config/FileLocator.php b/Config/FileLocator.php
index 5dc82b33dc..a302419701 100644
--- a/Config/FileLocator.php
+++ b/Config/FileLocator.php
@@ -70,11 +70,11 @@ public function locate($file, $currentPath = null, $first = true)
             // no need to trigger deprecations when the loaded file is given as absolute path
             foreach ($this->paths as $deprecatedPath) {
                 foreach ((array) $locations as $location) {
-                    if (null !== $currentPath && 0 === strpos($location, $currentPath)) {
+                    if (null !== $currentPath && str_starts_with($location, $currentPath)) {
                         return $locations;
                     }
 
-                    if (0 === strpos($location, $deprecatedPath) && (null === $currentPath || false === strpos($location, $currentPath))) {
+                    if (str_starts_with($location, $deprecatedPath) && (null === $currentPath || !str_contains($location, $currentPath))) {
                         $deprecation = sprintf('Loading the file "%s" from the global resource directory "%s" is deprecated since Symfony 4.4 and will be removed in 5.0.', $file, $deprecatedPath);
                     }
                 }
diff --git a/Controller/ControllerResolver.php b/Controller/ControllerResolver.php
index 9c2fdd9807..c3df8f9571 100644
--- a/Controller/ControllerResolver.php
+++ b/Controller/ControllerResolver.php
@@ -106,7 +106,7 @@ public function getController(Request $request)
      */
     protected function createController($controller)
     {
-        if (false === strpos($controller, '::')) {
+        if (!str_contains($controller, '::')) {
             $controller = $this->instantiateController($controller);
 
             if (!\is_callable($controller)) {
@@ -154,7 +154,7 @@ protected function instantiateController($class)
     private function getControllerError($callable): string
     {
         if (\is_string($callable)) {
-            if (false !== strpos($callable, '::')) {
+            if (str_contains($callable, '::')) {
                 $callable = explode('::', $callable, 2);
             } else {
                 return sprintf('Function "%s" does not exist.', $callable);
@@ -195,7 +195,7 @@ private function getControllerError($callable): string
         foreach ($collection as $item) {
             $lev = levenshtein($method, $item);
 
-            if ($lev <= \strlen($method) / 3 || false !== strpos($item, $method)) {
+            if ($lev <= \strlen($method) / 3 || str_contains($item, $method)) {
                 $alternatives[] = $item;
             }
         }
diff --git a/DataCollector/DumpDataCollector.php b/DataCollector/DumpDataCollector.php
index a3cf2147cb..a66224b6f4 100644
--- a/DataCollector/DumpDataCollector.php
+++ b/DataCollector/DumpDataCollector.php
@@ -120,11 +120,11 @@ public function collect(Request $request, Response $response/*, \Throwable $exce
         if (!$this->requestStack
             || !$response->headers->has('X-Debug-Token')
             || $response->isRedirection()
-            || ($response->headers->has('Content-Type') && false === strpos($response->headers->get('Content-Type'), 'html'))
+            || ($response->headers->has('Content-Type') && !str_contains($response->headers->get('Content-Type'), 'html'))
             || 'html' !== $request->getRequestFormat()
             || false === strripos($response->getContent(), '</body>')
         ) {
-            if ($response->headers->has('Content-Type') && false !== strpos($response->headers->get('Content-Type'), 'html')) {
+            if ($response->headers->has('Content-Type') && str_contains($response->headers->get('Content-Type'), 'html')) {
                 $dumper = new HtmlDumper('php://output', $this->charset);
                 $dumper->setDisplayOptions(['fileLinkFormat' => $this->fileLinkFormat]);
             } else {
diff --git a/DataCollector/MemoryDataCollector.php b/DataCollector/MemoryDataCollector.php
index 7ffcdab41d..ff0ccd9fa9 100644
--- a/DataCollector/MemoryDataCollector.php
+++ b/DataCollector/MemoryDataCollector.php
@@ -104,9 +104,9 @@ private function convertToBytes(string $memoryLimit)
 
         $memoryLimit = strtolower($memoryLimit);
         $max = strtolower(ltrim($memoryLimit, '+'));
-        if (0 === strpos($max, '0x')) {
+        if (str_starts_with($max, '0x')) {
             $max = \intval($max, 16);
-        } elseif (0 === strpos($max, '0')) {
+        } elseif (str_starts_with($max, '0')) {
             $max = \intval($max, 8);
         } else {
             $max = (int) $max;
diff --git a/DataCollector/RequestDataCollector.php b/DataCollector/RequestDataCollector.php
index f40c2fb9f6..2a3f6ce514 100644
--- a/DataCollector/RequestDataCollector.php
+++ b/DataCollector/RequestDataCollector.php
@@ -394,7 +394,7 @@ public function getName()
      */
     protected function parseController($controller)
     {
-        if (\is_string($controller) && false !== strpos($controller, '::')) {
+        if (\is_string($controller) && str_contains($controller, '::')) {
             $controller = explode('::', $controller);
         }
 
@@ -431,7 +431,7 @@ protected function parseController($controller)
                 'line' => $r->getStartLine(),
             ];
 
-            if (false !== strpos($r->name, '{closure}')) {
+            if (str_contains($r->name, '{closure}')) {
                 return $controller;
             }
             $controller['method'] = $r->name;
diff --git a/Debug/FileLinkFormatter.php b/Debug/FileLinkFormatter.php
index 79755a8ad7..27c71708b2 100644
--- a/Debug/FileLinkFormatter.php
+++ b/Debug/FileLinkFormatter.php
@@ -50,7 +50,7 @@ public function format($file, $line)
     {
         if ($fmt = $this->getFileLinkFormat()) {
             for ($i = 1; isset($fmt[$i]); ++$i) {
-                if (0 === strpos($file, $k = $fmt[$i++])) {
+                if (str_starts_with($file, $k = $fmt[$i++])) {
                     $file = substr_replace($file, $fmt[$i], 0, \strlen($k));
                     break;
                 }
diff --git a/DependencyInjection/AddAnnotatedClassesToCachePass.php b/DependencyInjection/AddAnnotatedClassesToCachePass.php
index 17a5f7f02e..9825151ab0 100644
--- a/DependencyInjection/AddAnnotatedClassesToCachePass.php
+++ b/DependencyInjection/AddAnnotatedClassesToCachePass.php
@@ -62,7 +62,7 @@ private function expandClasses(array $patterns, array $classes): array
 
         // Explicit classes declared in the patterns are returned directly
         foreach ($patterns as $key => $pattern) {
-            if (!str_ends_with($pattern, '\\') && false === strpos($pattern, '*')) {
+            if (!str_ends_with($pattern, '\\') && !str_contains($pattern, '*')) {
                 unset($patterns[$key]);
                 $expanded[] = ltrim($pattern, '\\');
             }
@@ -127,10 +127,10 @@ private function patternsToRegexps(array $patterns): array
 
     private function matchAnyRegexps(string $class, array $regexps): bool
     {
-        $isTest = false !== strpos($class, 'Test');
+        $isTest = str_contains($class, 'Test');
 
         foreach ($regexps as $regex) {
-            if ($isTest && false === strpos($regex, 'Test')) {
+            if ($isTest && !str_contains($regex, 'Test')) {
                 continue;
             }
 
diff --git a/EventListener/AbstractTestSessionListener.php b/EventListener/AbstractTestSessionListener.php
index 86f179add7..25be3b3907 100644
--- a/EventListener/AbstractTestSessionListener.php
+++ b/EventListener/AbstractTestSessionListener.php
@@ -81,7 +81,7 @@ public function onKernelResponse(FilterResponseEvent $event)
         if ($session instanceof Session ? !$session->isEmpty() || (null !== $this->sessionId && $session->getId() !== $this->sessionId) : $wasStarted) {
             $params = session_get_cookie_params() + ['samesite' => null];
             foreach ($this->sessionOptions as $k => $v) {
-                if (0 === strpos($k, 'cookie_')) {
+                if (str_starts_with($k, 'cookie_')) {
                     $params[substr($k, 7)] = $v;
                 }
             }
diff --git a/Exception/ControllerDoesNotReturnResponseException.php b/Exception/ControllerDoesNotReturnResponseException.php
index 1e87690ff1..54c80be90f 100644
--- a/Exception/ControllerDoesNotReturnResponseException.php
+++ b/Exception/ControllerDoesNotReturnResponseException.php
@@ -38,7 +38,7 @@ public function __construct(string $message, callable $controller, string $file,
 
     private function parseControllerDefinition(callable $controller): ?array
     {
-        if (\is_string($controller) && false !== strpos($controller, '::')) {
+        if (\is_string($controller) && str_contains($controller, '::')) {
             $controller = explode('::', $controller);
         }
 
diff --git a/HttpCache/AbstractSurrogate.php b/HttpCache/AbstractSurrogate.php
index 472d87e483..3385940243 100644
--- a/HttpCache/AbstractSurrogate.php
+++ b/HttpCache/AbstractSurrogate.php
@@ -57,7 +57,7 @@ public function hasSurrogateCapability(Request $request)
             return false;
         }
 
-        return false !== strpos($value, sprintf('%s/1.0', strtoupper($this->getName())));
+        return str_contains($value, sprintf('%s/1.0', strtoupper($this->getName())));
     }
 
     /**
diff --git a/HttpCache/Esi.php b/HttpCache/Esi.php
index 0bad63e748..829f4ac643 100644
--- a/HttpCache/Esi.php
+++ b/HttpCache/Esi.php
@@ -37,7 +37,7 @@ public function getName()
      */
     public function addSurrogateControl(Response $response)
     {
-        if (false !== strpos($response->getContent(), '<esi:include')) {
+        if (str_contains($response->getContent(), '<esi:include')) {
             $response->headers->set('Surrogate-Control', 'content="ESI/1.0"');
         }
     }
diff --git a/HttpCache/Ssi.php b/HttpCache/Ssi.php
index 6dba4e11df..a2856f2760 100644
--- a/HttpCache/Ssi.php
+++ b/HttpCache/Ssi.php
@@ -34,7 +34,7 @@ public function getName()
      */
     public function addSurrogateControl(Response $response)
     {
-        if (false !== strpos($response->getContent(), '<!--#include')) {
+        if (str_contains($response->getContent(), '<!--#include')) {
             $response->headers->set('Surrogate-Control', 'content="SSI/1.0"');
         }
     }
diff --git a/Kernel.php b/Kernel.php
index 1c46d1cbb5..0040f76988 100644
--- a/Kernel.php
+++ b/Kernel.php
@@ -255,17 +255,17 @@ public function locateResource($name/*, $dir = null, $first = true, $triggerDepr
             throw new \InvalidArgumentException(sprintf('A resource name must start with @ ("%s" given).', $name));
         }
 
-        if (false !== strpos($name, '..')) {
+        if (str_contains($name, '..')) {
             throw new \RuntimeException(sprintf('File name "%s" contains invalid characters (..).', $name));
         }
 
         $bundleName = substr($name, 1);
         $path = '';
-        if (false !== strpos($bundleName, '/')) {
+        if (str_contains($bundleName, '/')) {
             [$bundleName, $path] = explode('/', $bundleName, 2);
         }
 
-        $isResource = 0 === strpos($path, 'Resources') && null !== $dir;
+        $isResource = str_starts_with($path, 'Resources') && null !== $dir;
         $overridePath = substr($path, 9);
         $bundle = $this->getBundle($bundleName);
         $files = [];
@@ -471,7 +471,7 @@ protected function build(ContainerBuilder $container)
     protected function getContainerClass()
     {
         $class = static::class;
-        $class = false !== strpos($class, "@anonymous\0") ? get_parent_class($class).str_replace('.', '_', ContainerBuilder::hash($class)) : $class;
+        $class = str_contains($class, "@anonymous\0") ? get_parent_class($class).str_replace('.', '_', ContainerBuilder::hash($class)) : $class;
         $class = $this->name.str_replace('\\', '_', $class).ucfirst($this->environment).($this->debug ? 'Debug' : '').'Container';
 
         if (!preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/', $class)) {
diff --git a/Log/Logger.php b/Log/Logger.php
index 3922d2fe68..3e1db33466 100644
--- a/Log/Logger.php
+++ b/Log/Logger.php
@@ -88,7 +88,7 @@ public function log($level, $message, array $context = [])
 
     private function format(string $level, string $message, array $context, bool $prefixDate = true): string
     {
-        if (false !== strpos($message, '{')) {
+        if (str_contains($message, '{')) {
             $replacements = [];
             foreach ($context as $key => $val) {
                 if (null === $val || is_scalar($val) || (\is_object($val) && method_exists($val, '__toString'))) {
diff --git a/Profiler/FileProfilerStorage.php b/Profiler/FileProfilerStorage.php
index b74563ac13..1ef58dc74c 100644
--- a/Profiler/FileProfilerStorage.php
+++ b/Profiler/FileProfilerStorage.php
@@ -34,7 +34,7 @@ class FileProfilerStorage implements ProfilerStorageInterface
      */
     public function __construct(string $dsn)
     {
-        if (0 !== strpos($dsn, 'file:')) {
+        if (!str_starts_with($dsn, 'file:')) {
             throw new \RuntimeException(sprintf('Please check your configuration. You are trying to use FileStorage with an invalid dsn "%s". The expected format is "file:/path/to/the/storage/folder".', $dsn));
         }
         $this->folder = substr($dsn, 5);
@@ -64,7 +64,7 @@ public function find($ip, $url, $limit, $method, $start = null, $end = null, $st
             [$csvToken, $csvIp, $csvMethod, $csvUrl, $csvTime, $csvParent, $csvStatusCode] = $values;
             $csvTime = (int) $csvTime;
 
-            if ($ip && false === strpos($csvIp, $ip) || $url && false === strpos($csvUrl, $url) || $method && false === strpos($csvMethod, $method) || $statusCode && false === strpos($csvStatusCode, $statusCode)) {
+            if ($ip && !str_contains($csvIp, $ip) || $url && !str_contains($csvUrl, $url) || $method && !str_contains($csvMethod, $method) || $statusCode && !str_contains($csvStatusCode, $statusCode)) {
                 continue;
             }
 
diff --git a/Tests/EventListener/RouterListenerTest.php b/Tests/EventListener/RouterListenerTest.php
index cc46fd8db5..38863e2753 100644
--- a/Tests/EventListener/RouterListenerTest.php
+++ b/Tests/EventListener/RouterListenerTest.php
@@ -60,7 +60,7 @@ public function testPort($defaultHttpPort, $defaultHttpsPort, $uri, $expectedHtt
 
         $this->assertEquals($expectedHttpPort, $context->getHttpPort());
         $this->assertEquals($expectedHttpsPort, $context->getHttpsPort());
-        $this->assertEquals(0 === strpos($uri, 'https') ? 'https' : 'http', $context->getScheme());
+        $this->assertEquals(str_starts_with($uri, 'https') ? 'https' : 'http', $context->getScheme());
     }
 
     public function getPortData()