diff -up ./phpunit.rpm ./phpunit
--- ./phpunit.rpm	2024-03-21 10:23:39.000000000 +0100
+++ ./phpunit	2024-03-21 14:04:08.699638712 +0100
@@ -46,27 +46,13 @@ if (isset($GLOBALS['_composer_autoload_p
     define('PHPUNIT_COMPOSER_INSTALL', $GLOBALS['_composer_autoload_path']);
 
     unset($GLOBALS['_composer_autoload_path']);
-} else {
-    foreach (array(__DIR__ . '/../../autoload.php', __DIR__ . '/../vendor/autoload.php', __DIR__ . '/vendor/autoload.php') as $file) {
-        if (file_exists($file)) {
-            define('PHPUNIT_COMPOSER_INSTALL', $file);
-
-            break;
-        }
-    }
 
-    unset($file);
-}
-
-if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
-    fwrite(
-        STDERR,
-        'You need to set up the project dependencies using Composer:' . PHP_EOL . PHP_EOL .
-        '    composer install' . PHP_EOL . PHP_EOL .
-        'You can learn all about Composer on https://getcomposer.org/.' . PHP_EOL
-    );
+} else if (file_exists('./vendor/phpunit/phpunit/phpunit') && file_exists('./vendor/autoload.php')) {
+    echo "\n==== Redirecting to composer installed version in vendor/phpunit ====\n\n";
+    define ('PHPUNIT_COMPOSER_INSTALL', realpath('./vendor/autoload.php'));
 
-    die(1);
+} else {
+    define ('PHPUNIT_COMPOSER_INSTALL', '/usr/share/php/PHPUnit11/autoload.php');
 }
 
 require PHPUNIT_COMPOSER_INSTALL;
@@ -101,4 +87,13 @@ if ([] !== $unavailableExtensions) {
 
 unset($requiredExtensions, $unavailableExtensions);
 
-exit((new PHPUnit\TextUI\Application)->run($_SERVER['argv']));
+if (class_exists('PHPUnit\\TextUI\\Application')) {
+    // PHPUnit v10 or newer
+    exit((new PHPUnit\TextUI\Application)->run($_SERVER['argv']));
+} else if (class_exists('PHPUnit_TextUI_Command')) {
+    // PHPUnit v5 or older
+    PHPUnit_TextUI_Command::main();
+} else {
+    // PHPUnit v6 to v9
+    PHPUnit\TextUI\Command::main();
+}
diff -up ./src/TextUI/Command/Commands/VersionCheckCommand.php.rpm ./src/TextUI/Command/Commands/VersionCheckCommand.php
--- ./src/TextUI/Command/Commands/VersionCheckCommand.php.rpm	2024-03-21 10:23:39.000000000 +0100
+++ ./src/TextUI/Command/Commands/VersionCheckCommand.php	2024-03-21 14:04:31.164578940 +0100
@@ -24,7 +24,7 @@ final readonly class VersionCheckCommand
     public function execute(): Result
     {
         $latestVersion           = file_get_contents('https://phar.phpunit.de/latest-version-of/phpunit');
-        $latestCompatibleVersion = @file_get_contents('https://phar.phpunit.de/latest-version-of/phpunit-' . Version::majorVersionNumber());
+        $latestCompatibleVersion = @file_get_contents('https://phar.phpunit.de/latest-version-of/phpunit-' . $major=Version::majorVersionNumber());
 
         $notLatest           = version_compare($latestVersion, Version::id(), '>');
         $notLatestCompatible = false;
@@ -39,7 +39,7 @@ final readonly class VersionCheckCommand
             );
         }
 
-        $buffer = 'You are not using the latest version of PHPUnit.' . PHP_EOL;
+        $buffer = 'You are not using the latest version of PHPUnit.' . PHP_EOL . PHP_EOL;
 
         if ($notLatestCompatible) {
             $buffer .= sprintf(
@@ -47,6 +47,7 @@ final readonly class VersionCheckCommand
                 Version::id(),
                 $latestCompatibleVersion,
             );
+            $buffer .= sprintf('Try a system update for new phpunit%s package.' . PHP_EOL . PHP_EOL, $major);
         }
 
         if ($notLatest) {
@@ -54,6 +55,9 @@ final readonly class VersionCheckCommand
                 'The latest version is PHPUnit %s.' . PHP_EOL,
                 $latestVersion,
             );
+            if ($major !== ($new = (int)explode('.', $latestVersion)[0])) {
+               $buffer .= sprintf('Try to install and use the phpunit%d command.' . PHP_EOL . PHP_EOL, $new);
+            }
         }
 
         return Result::from($buffer, Result::FAILURE);
diff -up ./src/TextUI/Configuration/Xml/SchemaFinder.php.rpm ./src/TextUI/Configuration/Xml/SchemaFinder.php
--- ./src/TextUI/Configuration/Xml/SchemaFinder.php.rpm	2024-03-21 10:23:39.000000000 +0100
+++ ./src/TextUI/Configuration/Xml/SchemaFinder.php	2024-03-21 14:04:08.699638712 +0100
@@ -75,6 +75,6 @@ final readonly class SchemaFinder
             return __PHPUNIT_PHAR_ROOT__ . '/';
         }
 
-        return __DIR__ . '/../../../../';
+        return __DIR__ . '/../../../';
     }
 }
diff -up ./tests/bootstrap.php.rpm ./tests/bootstrap.php
--- ./tests/bootstrap.php.rpm	2024-03-21 10:23:39.000000000 +0100
+++ ./tests/bootstrap.php	2024-03-21 14:04:08.699638712 +0100
@@ -11,8 +11,8 @@ if (!defined('TEST_FILES_PATH')) {
     define('TEST_FILES_PATH', __DIR__ . DIRECTORY_SEPARATOR . '_files' . DIRECTORY_SEPARATOR);
 }
 
-$composer = file_exists(__DIR__ . '/../vendor/autoload.php');
-$phar     = file_exists(__DIR__ . '/autoload.php');
+$composer = true;
+$phar     = false;
 
 if ($composer && $phar) {
     print 'More than one test fixture autoloader is available, exiting.' . PHP_EOL;
@@ -28,10 +28,15 @@ if (!$composer && !$phar) {
 
 if ($composer) {
     if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
-        define('PHPUNIT_COMPOSER_INSTALL', dirname(__DIR__) . '/vendor/autoload.php');
+        define('PHPUNIT_COMPOSER_INSTALL', '@PATH@/autoload.php');
     }
 
-    require_once __DIR__ . '/../vendor/autoload.php';
+    require_once PHPUNIT_COMPOSER_INSTALL;
+    require_once __DIR__ . '/_files/CoverageNamespacedFunctionTest.php';
+    require_once __DIR__ . '/_files/CoveredFunction.php';
+    require_once __DIR__ . '/_files/Generator.php';
+    require_once __DIR__ . '/_files/NamespaceCoveredFunction.php';
+    require_once __DIR__ . '/autoload.php';
 }
 
 if ($phar) {