diff --git a/composer.json b/composer.json
index d418716..3334194 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,8 @@
     "require": {
         "php": ">=7.4",
         "friendsofphp/php-cs-fixer": "v3.75.0",
-        "adamwojs/php-cs-fixer-phpdoc-force-fqcn": "^2.0"
+        "adamwojs/php-cs-fixer-phpdoc-force-fqcn": "^2.0",
+        "composer-runtime-api": ">=2.0"
     },
     "require-dev": {
         "roave/security-advisories": "dev-master",
@@ -29,7 +30,7 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "Ibexa\\Tests\\CodeStyle\\PhpCsFixer\\": "tests/lib/"
+            "Ibexa\\Tests\\CodeStyle\\": "tests/lib/"
         }
     },
     "scripts": {
diff --git a/src/lib/PhpCsFixer/InternalConfigFactory.php b/src/lib/PhpCsFixer/InternalConfigFactory.php
index e9b6f87..2035fd9 100644
--- a/src/lib/PhpCsFixer/InternalConfigFactory.php
+++ b/src/lib/PhpCsFixer/InternalConfigFactory.php
@@ -8,6 +8,7 @@
 
 namespace Ibexa\CodeStyle\PhpCsFixer;
 
+use Composer\InstalledVersions;
 use Ibexa\CodeStyle\PhpCsFixer\Sets\RuleSetInterface;
 use PhpCsFixer\ConfigInterface;
 
@@ -42,7 +43,31 @@ public function withRuleSet(RuleSetInterface $ruleSet): self
 
     public function getRuleSet(): RuleSetInterface
     {
-        return $this->ruleSet ??= new Sets\Ibexa46RuleSet();
+        return $this->ruleSet ??= $this->createRuleSetFromPackage(InstalledVersions::getRootPackage());
+    }
+
+    /**
+     * @param array{name: string, version: string, pretty_version?: string} $package
+     */
+    private function createRuleSetFromPackage(array $package): RuleSetInterface
+    {
+        if (!str_starts_with($package['name'], 'ibexa/')) {
+            return new Sets\Ibexa46RuleSet();
+        }
+
+        $version = $package['pretty_version'] ?? $package['version'];
+        if (str_starts_with($version, 'dev-') || $version === '*') {
+            return new Sets\Ibexa50RuleSet();
+        }
+
+        // Remove any suffix like -dev, -alpha, etc.
+        $version = (string)preg_replace('/-.*$/', '', $version);
+
+        if (version_compare($version, '5.0.0', '>=')) {
+            return new Sets\Ibexa50RuleSet();
+        }
+
+        return new Sets\Ibexa46RuleSet();
     }
 
     public function buildConfig(): ConfigInterface
diff --git a/tests/lib/PhpCsFixer/InternalConfigFactoryTest.php b/tests/lib/PhpCsFixer/InternalConfigFactoryTest.php
new file mode 100644
index 0000000..71ef115
--- /dev/null
+++ b/tests/lib/PhpCsFixer/InternalConfigFactoryTest.php
@@ -0,0 +1,93 @@
+<?php
+
+/**
+ * @copyright Copyright (C) Ibexa AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace Ibexa\Tests\CodeStyle\PhpCsFixer;
+
+use Ibexa\CodeStyle\PhpCsFixer\InternalConfigFactory;
+use Ibexa\CodeStyle\PhpCsFixer\Sets\Ibexa46RuleSet;
+use Ibexa\CodeStyle\PhpCsFixer\Sets\Ibexa50RuleSet;
+use PHPUnit\Framework\TestCase;
+use ReflectionClass;
+use ReflectionMethod;
+
+/**
+ * @covers \Ibexa\CodeStyle\PhpCsFixer\InternalConfigFactory
+ */
+final class InternalConfigFactoryTest extends TestCase
+{
+    private InternalConfigFactory $factory;
+
+    private ReflectionMethod $createRuleSetFromPackage;
+
+    protected function setUp(): void
+    {
+        $this->factory = new InternalConfigFactory();
+        $reflection = new ReflectionClass(InternalConfigFactory::class);
+
+        // This method is private because we don't want it to be part of the public API.
+        // We can't test getRuleSet since it internally uses InstalledVersions::getRootPackage(), which cannot be mocked.
+        $this->createRuleSetFromPackage = $reflection->getMethod('createRuleSetFromPackage');
+        $this->createRuleSetFromPackage->setAccessible(true);
+    }
+
+    /**
+     * @dataProvider provideRuleSetTestCases
+     */
+    public function testVersionBasedRuleSetSelection(array $package, string $expectedRuleSetClass): void
+    {
+        $ruleSet = $this->createRuleSetFromPackage->invoke($this->factory, $package);
+
+        self::assertInstanceOf($expectedRuleSetClass, $ruleSet);
+    }
+
+    public function provideRuleSetTestCases(): array
+    {
+        return [
+            'non_ibexa_package' => [
+                ['name' => 'vendor/package', 'version' => '1.0.0'],
+                Ibexa46RuleSet::class,
+            ],
+            'ibexa_package_4_6' => [
+                ['name' => 'ibexa/core', 'version' => '4.6.0'],
+                Ibexa46RuleSet::class,
+            ],
+            'ibexa_package_5_0' => [
+                ['name' => 'ibexa/core', 'version' => '5.0.0'],
+                Ibexa50RuleSet::class,
+            ],
+            'ibexa_package_5_1' => [
+                ['name' => 'ibexa/core', 'version' => '5.1.0'],
+                Ibexa50RuleSet::class,
+            ],
+            'ibexa_package_dev_master' => [
+                ['name' => 'ibexa/core', 'version' => 'dev-master'],
+                Ibexa50RuleSet::class,
+            ],
+            'ibexa_package_with_pretty_version' => [
+                ['name' => 'ibexa/core', 'version' => '5.0.0', 'pretty_version' => '5.0.0-alpha1'],
+                Ibexa50RuleSet::class,
+            ],
+            'ibexa_package_wildcard' => [
+                ['name' => 'ibexa/core', 'version' => '*'],
+                Ibexa50RuleSet::class,
+            ],
+            'ibexa_package_4_6_with_suffix' => [
+                ['name' => 'ibexa/core', 'version' => '4.6.0-beta1'],
+                Ibexa46RuleSet::class,
+            ],
+        ];
+    }
+
+    public function testWithRuleSet(): void
+    {
+        $customRuleSet = new Ibexa46RuleSet();
+        $this->factory->withRuleSet($customRuleSet);
+
+        self::assertSame($customRuleSet, $this->factory->getRuleSet());
+    }
+}
diff --git a/tests/lib/Sets/Ibexa46RuleSetTest.php b/tests/lib/PhpCsFixer/Sets/Ibexa46RuleSetTest.php
similarity index 100%
rename from tests/lib/Sets/Ibexa46RuleSetTest.php
rename to tests/lib/PhpCsFixer/Sets/Ibexa46RuleSetTest.php
diff --git a/tests/lib/Sets/Ibexa50RuleSetTest.php b/tests/lib/PhpCsFixer/Sets/Ibexa50RuleSetTest.php
similarity index 100%
rename from tests/lib/Sets/Ibexa50RuleSetTest.php
rename to tests/lib/PhpCsFixer/Sets/Ibexa50RuleSetTest.php
diff --git a/tests/lib/Sets/expected_rules/4_6_rule_set/local_rules.php b/tests/lib/PhpCsFixer/Sets/expected_rules/4_6_rule_set/local_rules.php
similarity index 100%
rename from tests/lib/Sets/expected_rules/4_6_rule_set/local_rules.php
rename to tests/lib/PhpCsFixer/Sets/expected_rules/4_6_rule_set/local_rules.php
diff --git a/tests/lib/Sets/expected_rules/4_6_rule_set/php_cs_fixer_rules.php b/tests/lib/PhpCsFixer/Sets/expected_rules/4_6_rule_set/php_cs_fixer_rules.php
similarity index 100%
rename from tests/lib/Sets/expected_rules/4_6_rule_set/php_cs_fixer_rules.php
rename to tests/lib/PhpCsFixer/Sets/expected_rules/4_6_rule_set/php_cs_fixer_rules.php
diff --git a/tests/lib/Sets/expected_rules/5_0_rule_set/local_rules.php b/tests/lib/PhpCsFixer/Sets/expected_rules/5_0_rule_set/local_rules.php
similarity index 100%
rename from tests/lib/Sets/expected_rules/5_0_rule_set/local_rules.php
rename to tests/lib/PhpCsFixer/Sets/expected_rules/5_0_rule_set/local_rules.php
diff --git a/tests/lib/Sets/expected_rules/5_0_rule_set/php_cs_fixer_rules.php b/tests/lib/PhpCsFixer/Sets/expected_rules/5_0_rule_set/php_cs_fixer_rules.php
similarity index 100%
rename from tests/lib/Sets/expected_rules/5_0_rule_set/php_cs_fixer_rules.php
rename to tests/lib/PhpCsFixer/Sets/expected_rules/5_0_rule_set/php_cs_fixer_rules.php