diff --git a/composer.json b/composer.json
index e5aa1c444c..e11839c850 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
     ],
     "require": {
         "php": ">=8.4",
-        "composer/pcre": "^3.3.2",
+        "composer/pcre": "^3.4",
         "composer/xdebug-handler": "^3.0.5",
         "entropy/entropy": "^0.4",
         "friendsofphp/php-cs-fixer": "^3.95.5",
@@ -37,7 +37,7 @@
         "symplify/phpstan-rules": "^14.11",
         "symplify/vendor-patches": "^11.5",
         "tomasvotruba/class-leak": "^2.1.7",
-        "tomasvotruba/type-coverage": "^2.1",
+        "tomasvotruba/type-coverage": "^2.2",
         "tomasvotruba/unused-public": "^2.2",
         "tracy/tracy": "^2.12"
     },
diff --git a/phpstan.neon b/phpstan.neon
index ace8e7cdc5..917a25e542 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -7,7 +7,8 @@ parameters:
     checkMissingCallableSignature: true
 
     # symplify - see https://github.com/symplify/phpstan-rules#usage
-    pathStrings: true
+    symplify:
+        pathStrings: true
 
     paths:
         - packages
diff --git a/src/DependencyInjection/ServiceContainerFactory.php b/src/DependencyInjection/ServiceContainerFactory.php
index 3286a8822b..606431bb8e 100644
--- a/src/DependencyInjection/ServiceContainerFactory.php
+++ b/src/DependencyInjection/ServiceContainerFactory.php
@@ -4,6 +4,7 @@
 
 namespace Symplify\EasyCodingStandard\DependencyInjection;
 
+use Closure;
 use Entropy\Container\Container;
 use PHP_CodeSniffer\Util\Tokens;
 use PhpCsFixer\Differ\DifferInterface;
@@ -68,6 +69,18 @@ static function (Container $container): EasyCodingStandardStyle {
             $configClosure = require $configFile;
             Assert::isCallable($configClosure);
 
+            if ($configClosure instanceof Closure && ! defined('PHPUNIT_COMPOSER_INSTALL')) {
+                /** @var SymfonyStyle $symfonyStyle */
+                $symfonyStyle = $ecsConfig->make(SymfonyStyle::class);
+                $symfonyStyle->warning(sprintf(
+                    'The "return function (ECSConfig $ecsConfig): void {}" config format is deprecated. Use "return ECSConfig::configure()" fluent API instead in "%s".',
+                    $configFile
+                ));
+
+                // give the user a moment to notice the deprecation warning
+                sleep(5);
+            }
+
             $configClosure($ecsConfig);
         }
 
diff --git a/templates/ecs.php.dist b/templates/ecs.php.dist
index f6f57eb6d5..a479fe7bed 100644
--- a/templates/ecs.php.dist
+++ b/templates/ecs.php.dist
@@ -9,6 +9,8 @@ return ECSConfig::configure()
     ->withPaths([
 __PATHS__
     ])
+    // include *.php files in the root directory
+    ->withRootFiles()
 
     // add a single rule
     ->withRules([
@@ -18,4 +20,9 @@ __PATHS__
     // add sets - group of rules, from easiest to more complex ones
     // uncomment one, apply one, commit, PR, merge and repeat
 __PREPARED_SETS__
-    ;
+
+    // ...but first: take it step by step
+    ->withSpacesLevel(0)
+    ->withArrayLevel(0)
+    ->withControlStructuresLevel(0)
+    ->withDocblockLevel(0);
diff --git a/tests/DependencyInjection/ConfigurationFileSource/deprecated-closure-config.php b/tests/DependencyInjection/ConfigurationFileSource/deprecated-closure-config.php
new file mode 100644
index 0000000000..9500565ce3
--- /dev/null
+++ b/tests/DependencyInjection/ConfigurationFileSource/deprecated-closure-config.php
@@ -0,0 +1,8 @@
+<?php
+
+declare(strict_types=1);
+
+use Symplify\EasyCodingStandard\Config\ECSConfig;
+
+return static function (ECSConfig $ecsConfig): void {
+};
diff --git a/tests/DependencyInjection/ConfigurationFileTest.php b/tests/DependencyInjection/ConfigurationFileTest.php
index 7d4ccf3b6d..b467529e69 100644
--- a/tests/DependencyInjection/ConfigurationFileTest.php
+++ b/tests/DependencyInjection/ConfigurationFileTest.php
@@ -31,4 +31,13 @@ public function testIncludeConfig(): void
         $sniffFileProcessor = $this->make(SniffFileProcessor::class);
         $this->assertCount(1, $sniffFileProcessor->getCheckers());
     }
+
+    public function testDeprecatedClosureConfig(): void
+    {
+        // the old closure config format is deprecated, but still loads
+        $this->createContainerWithConfigs([__DIR__ . '/ConfigurationFileSource/deprecated-closure-config.php']);
+
+        $fixerFileProcessor = $this->make(FixerFileProcessor::class);
+        $this->assertCount(0, $fixerFileProcessor->getCheckers());
+    }
 }