diff --git a/.circleci/config.yml b/.circleci/config.yml
index 18847d3..c35a017 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,50 +1,49 @@
-version: 2
+version: 2.1
+
+executors:
+  php83:
+    docker:
+      - image: skpr/php-cli:8.3-v2-latest
 
 workflows:
-  version: 2
   build:
     jobs:
-      - build_lowest
-      - build_highest
-
-defaults: &defaults
-  docker:
-    - image: previousnext/php-apache:7.2-3.x-dev
-  working_directory: /data
-  steps:
-    - checkout
-    - restore_cache:
-        keys:
-          - deps-{{ arch }}
-    - run:
-        name: "Install Dependencies"
-        command: composer update --prefer-dist --no-progress --no-suggest --no-interaction ${PREFER_LOWEST}
-    - save_cache:
-        key: deps-{{ arch }}
-        paths:
-          - vendor
-    - run:
-        name: "Lint"
-        command: ./bin/phpcs
-    - run:
-        name: "Test"
-        command: |
-          mkdir -p ~/phpunit
-          ./bin/phpunit --testsuite unit --log-junit ~/phpunit/phpunit.xml
-    - store_test_results:
-        path: ~/phpunit
-    - store_artifacts:
-        path: ~/phpunit
+      - build:
+          matrix:
+            parameters:
+              php: ["php83"]
+              composer-opts: ["", "--prefer-lowest"]
 
 jobs:
-  build_lowest:
-    <<: *defaults
-    docker:
-      - image: previousnext/php-apache:7.1-3.x-dev
-
-    environment:
-      - PREFER_LOWEST: --prefer-lowest
-  build_highest:
-    <<: *defaults
-    environment:
-      - PREFER_LOWEST: ''
+  build:
+    parameters:
+      php:
+        type: executor
+      composer-opts:
+        type: string
+    executor: << parameters.php >>
+    working_directory: /data
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+            - deps-{{ arch }}
+      - run:
+          name: "Install Dependencies"
+          command: composer update --prefer-dist --no-progress --no-interaction << parameters.composer-opts >>
+      - save_cache:
+          key: deps-{{ arch }}
+          paths:
+            - vendor
+      - run:
+          name: "Lint"
+          command: ./bin/phpcs --runtime-set testVersion 8.0-
+      - run:
+          name: "Test"
+          command: |
+            mkdir -p ~/phpunit
+            ./bin/phpunit --log-junit ~/phpunit/phpunit.xml
+      - store_test_results:
+          path: ~/phpunit
+      - store_artifacts:
+          path: ~/phpunit
diff --git a/.gitignore b/.gitignore
index 9902d7b..6342d02 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 /bin
 /vendor
+/.phpunit.result.cache
 /composer.lock
diff --git a/composer.json b/composer.json
index d4b3162..73ec539 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,7 @@
 {
   "name": "previousnext/phpunit-finder",
   "description": "PHP lib for finding and outputting all tests from a phpunit.xml config file.",
+  "keywords": ["testing"],
   "license": "GPL-2.0-or-later",
   "authors": [
     {
@@ -13,12 +14,14 @@
     }
   ],
   "require": {
-    "php": "^7.1",
-    "phpunit/phpunit": "^6.5",
-    "symfony/console": "^3.4"
+    "php": "^8.1",
+    "phpunit/phpunit": "^10.5",
+    "symfony/console": "^6.4||^7"
   },
   "require-dev": {
-    "drupal/coder": ">=8.2.12"
+    "dealerdirect/phpcodesniffer-composer-installer": "^0.7.1",
+    "drupal/coder": "~8.3.12",
+    "phpcompatibility/php-compatibility": "^9.3"
   },
   "autoload": {
     "psr-4": {"PhpUnitFinder\\": "src/"}
@@ -32,6 +35,9 @@
     "preferred-install": {
       "*": "dist"
     },
-    "sort-packages": true
+    "sort-packages": true,
+    "allow-plugins": {
+      "dealerdirect/phpcodesniffer-composer-installer": true
+    }
   }
 }
diff --git a/phpcs.xml b/phpcs.xml
index 7de9f55..e786749 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -1,26 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<ruleset name="phpunit-finder">
-  <description>PHP CodeSniffer configuration for PHPUnit Finder</description>
-  <!-- folders to scan -->
+<ruleset name="pnx-project">
+  <description>PHP Codesniffer configuration.</description>
   <file>./src</file>
-  <file>./tests</file>
-  <!-- extensions to scan -->
+  <exclude-pattern>./tests/bootstrap.php</exclude-pattern>
   <arg name="extensions" value="php"/>
-  <!-- additional arguments -->
   <arg name="report" value="full"/>
-  <!-- inherit from coder -->
-  <rule ref="./vendor/drupal/coder/coder_sniffer/Drupal"/>
-  <!-- Additional detailed sniff configuration -->
-  <!-- You can determine sniff names by running with -s flag -->
-  <!-- Example 1 - ignore Drupal.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
-    <rule ref="Drupal.NamingConventions.ValidFunctionName.ScopeNotCamelCaps">
-      <severity>0</severity>
-    </rule>
-  // End example 1 -->
-  <!-- Example 2 - ignore rule for specific files
-    <rule ref="Drupal.NamingConventions.ValidVariableName.LowerCamelName">
-      <exclude-pattern>OfferNormalizerTrait.php</exclude-pattern>
-      <exclude-pattern>TimeOfUseValidationTrait.php</exclude-pattern>
-    </rule>
-  // End example 2 -->
+  <arg name="colors"/>
+  <arg value="sp"/>
+  <rule ref="Drupal">
+    <!-- ignore for now -->
+    <exclude name="Drupal.Classes.UseGlobalClass.RedundantUseStatement" />
+  </rule>
+  <rule ref="PHPCompatibility"/>
+  <config name="testVersion" value="7.3-"/>
 </ruleset>
diff --git a/phpunit-finder b/phpunit-finder
index 5bf6278..5ab3c5c 100755
--- a/phpunit-finder
+++ b/phpunit-finder
@@ -5,10 +5,22 @@
  * Console application for PHPUnit Finder.
  */
 
-require __DIR__ . '/../../autoload.php';
+$autoload = [
+  __DIR__ . '/vendor/autoload.php',
+  dirname(__DIR__, 1) . '/vendor/autoload.php',
+  dirname(__DIR__, 2) . '/vendor/autoload.php',
+  dirname(__DIR__, 1) . '/autoload.php',
+  dirname(__DIR__, 2) . '/autoload.php',
+];
+foreach ($autoload as $file) {
+  if (file_exists($file)) {
+    require $file;
+    break;
+  }
+}
 
 const APP_NAME = 'PHPUnit Finder';
-const VERSION = '0.0.1';
+const VERSION = '2.x-dev';
 
 use PhpUnitFinder\FinderCommand;
 use Symfony\Component\Console\Application;
diff --git a/phpunit.xml b/phpunit.xml
index 4b29e2e..86e75cb 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,15 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-
 <!-- TODO set checkForUnintentionallyCoveredCode="true" once https://www.drupal.org/node/2626832 is resolved. -->
 <!-- PHPUnit expects functional tests to be run with either a privileged user
  or your current system user. See core/tests/README.md and
  https://www.drupal.org/node/2116263 for details.
 -->
-<phpunit bootstrap="tests/bootstrap.php" colors="true"
-         beStrictAboutTestsThatDoNotTestAnything="true"
-         beStrictAboutOutputDuringTests="true"
-         beStrictAboutChangesToGlobalState="true"
-         checkForUnintentionallyCoveredCode="false">
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="tests/bootstrap.php" colors="true" beStrictAboutTestsThatDoNotTestAnything="true" beStrictAboutOutputDuringTests="true" beStrictAboutChangesToGlobalState="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd">
   <php>
     <!-- Set error reporting to E_ALL. -->
     <ini name="error_reporting" value="32767"/>
@@ -21,19 +16,15 @@
     <testsuite name="unit">
       <directory>./tests/Unit</directory>
     </testsuite>
-    <testsuite name="functional">
-      <directory>./tests/Functional</directory>
-    </testsuite>
   </testsuites>
   <!-- Filter for coverage reports. -->
-  <filter>
-    <whitelist>
+  <source>
+    <include>
       <directory>./src</directory>
-      <!-- By definition test classes have no tests. -->
-      <exclude>
-        <directory suffix="Test.php">./</directory>
-        <directory suffix="TestBase.php">./</directory>
-      </exclude>
-    </whitelist>
-  </filter>
+    </include>
+    <exclude>
+      <directory suffix="Test.php">./</directory>
+      <directory suffix="TestBase.php">./</directory>
+    </exclude>
+  </source>
 </phpunit>
diff --git a/src/FinderCommand.php b/src/FinderCommand.php
index 770e9c2..1a8304c 100644
--- a/src/FinderCommand.php
+++ b/src/FinderCommand.php
@@ -3,8 +3,10 @@
 namespace PhpUnitFinder;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Util\Configuration;
-use ReflectionClass;
+use PHPUnit\TextUI\CliArguments\Builder;
+use PHPUnit\TextUI\Configuration\Registry;
+use PHPUnit\TextUI\XmlConfiguration\Loader;
+use PHPUnit\TextUI\XmlConfiguration\TestSuiteMapper;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
@@ -28,29 +30,38 @@ protected function configure() {
   /**
    * {@inheritdoc}
    */
-  protected function execute(InputInterface $input, OutputInterface $output) {
+  protected function execute(InputInterface $input, OutputInterface $output): int {
     $configFile = $input->getOption('config-file');
     $bootstrap = $input->getOption('bootstrap-file');
     include_once $bootstrap;
     $testSuites = $input->getArgument('test-suite');
-
-    $config = Configuration::getInstance($configFile);
-    if (empty($testSuites)) {
-      $testSuites = $config->getTestSuiteNames();
-    }
     $testFilenames = [];
-    foreach ($testSuites as $suiteName) {
-      $suite = $config->getTestSuiteConfiguration($suiteName);
-      foreach (new \RecursiveIteratorIterator($suite->getIterator()) as $test) {
+
+    $config = (new Loader())->load($configFile);
+
+    Registry::init(
+      (new Builder)->fromParameters([]),
+      $config,
+    );
+
+    foreach ($config->testSuite() as $suite) {
+      if ($testSuites && !in_array($suite->name(), $testSuites, TRUE)) {
+        continue;
+      }
+      $testSuite = (new TestSuiteMapper())->map($config->filename(), $config->testSuite(), $suite->name(), '');
+      foreach (new \RecursiveIteratorIterator($testSuite) as $test) {
         if ($test instanceof TestCase) {
-          $testFilenames[] = ((new ReflectionClass($test))->getFileName());
+          $testFilenames[] = ((new \ReflectionClass($test))->getFileName());
         }
       }
     }
+
     $testFilenames = array_unique($testFilenames);
     foreach ($testFilenames as $testFilename) {
       $output->writeln($testFilename);
     }
+
+    return 0;
   }
 
 }
diff --git a/tests/Unit/FinderTest.php b/tests/Unit/FinderTest.php
new file mode 100644
index 0000000..2a32874
--- /dev/null
+++ b/tests/Unit/FinderTest.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace PhpUnitFinder\Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+use PhpUnitFinder\FinderCommand;
+use Symfony\Component\Console\Tester\CommandTester;
+
+/**
+ * A test of the command functionality
+ */
+class FinderTest extends TestCase {
+
+  /**
+   * A stub test.
+   */
+  public function testDiscovery() {
+    $command = new CommandTester(new FinderCommand());
+    $command->execute([
+      '--config-file' => dirname(__DIR__) . '/fixtures/phpunit.xml'
+    ]);
+    $output = $command->getDisplay();
+    $this->assertNotNull($output);
+    if (method_exists($this, 'assertStringContainsString')) {
+      $this->assertStringContainsString('TestUnitTest.php', $output);
+      $this->assertStringContainsString('TestFunctionalTest.php', $output);
+      return;
+    }
+    $this->assertContains('TestUnitTest.php', $output);
+    $this->assertContains('TestFunctionalTest.php', $output);
+  }
+
+}
diff --git a/tests/Unit/StubTest.php b/tests/Unit/StubTest.php
deleted file mode 100644
index 105cc7e..0000000
--- a/tests/Unit/StubTest.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-namespace PhpUnitFinder\Tests\Unit;
-
-use PHPUnit\Framework\TestCase;
-
-/**
- * A stub test.
- */
-class StubTest extends TestCase {
-
-  /**
-   * A stub test.
-   */
-  public function testStub() {
-    $this->assertTrue(TRUE);
-  }
-
-}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 7ddf755..0bf42f5 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -4,9 +4,6 @@
  * @file
  * Boostrap for PHPUnit.
  */
-
-assert_options(ASSERT_ACTIVE, FALSE);
-
 $autoloader = __DIR__ . '/../vendor/autoload.php';
 $loader = require $autoloader;
 
diff --git a/tests/fixtures/phpunit.xml b/tests/fixtures/phpunit.xml
new file mode 100644
index 0000000..1fcab63
--- /dev/null
+++ b/tests/fixtures/phpunit.xml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- TODO set checkForUnintentionallyCoveredCode="true" once https://www.drupal.org/node/2626832 is resolved. -->
+<!-- PHPUnit expects functional tests to be run with either a privileged user
+ or your current system user. See core/tests/README.md and
+ https://www.drupal.org/node/2116263 for details.
+-->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="tests/bootstrap.php" colors="true" beStrictAboutTestsThatDoNotTestAnything="true" beStrictAboutOutputDuringTests="true" beStrictAboutChangesToGlobalState="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage>
+    <include>
+      <directory>./src</directory>
+    </include>
+    <exclude>
+      <directory suffix="Test.php">./</directory>
+      <directory suffix="TestBase.php">./</directory>
+    </exclude>
+  </coverage>
+  <php>
+    <!-- Set error reporting to E_ALL. -->
+    <ini name="error_reporting" value="32767"/>
+    <!-- Do not limit the amount of memory tests take to run. -->
+    <ini name="memory_limit" value="-1"/>
+    <const name="BOOTSTRAP_IS_PHPUNIT" value="true"/>
+  </php>
+  <testsuites>
+    <testsuite name="unit">
+      <directory>./tests/Unit</directory>
+    </testsuite>
+    <testsuite name="functional">
+      <directory>./tests/Functional</directory>
+    </testsuite>
+  </testsuites>
+  <!-- Filter for coverage reports. -->
+</phpunit>
diff --git a/tests/fixtures/tests/Functional/TestFunctionalTest.php b/tests/fixtures/tests/Functional/TestFunctionalTest.php
new file mode 100644
index 0000000..3ee4ed8
--- /dev/null
+++ b/tests/fixtures/tests/Functional/TestFunctionalTest.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace PhpUnitFinder\Tests\fixtures\tests\Functional;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Defines a test class.
+ */
+class TestFunctionalTest extends TestCase {
+
+  /**
+   * Tests something.
+   */
+  public function testSomething() {
+    $this->addToAssertionCount(1);
+  }
+
+}
diff --git a/tests/fixtures/tests/Unit/TestUnitTest.php b/tests/fixtures/tests/Unit/TestUnitTest.php
new file mode 100644
index 0000000..90f0829
--- /dev/null
+++ b/tests/fixtures/tests/Unit/TestUnitTest.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace PhpUnitFinder\Tests\fixtures\tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Defines a test class.
+ */
+class TestUnitTest extends TestCase {
+
+  /**
+   * Tests something.
+   */
+  public function testSomething() {
+    $this->addToAssertionCount(1);
+  }
+
+}