diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..29cc548
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+export XDEBUG_MODE=coverage
diff --git a/.gitattributes b/.gitattributes
index 6efd584..37e903a 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,6 +1,7 @@
 /tests export-ignore
 /.github export-ignore
 /resources/pp/*.pp export-ignore
+.envrc export-ignore
 phpunit.xml.dist export-ignore
 psalm.xml export-ignore
 phpcs.xml export-ignore
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f635610..70f8c20 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
 
       - name: Psalm
         uses: docker://vimeo/psalm-github-actions
@@ -18,7 +18,7 @@ jobs:
           composer_ignore_platform_reqs: true
 
       - name: Upload Security Analysis results to GitHub
-        uses: github/codeql-action/upload-sarif@v2
+        uses: github/codeql-action/upload-sarif@v4
         with:
           sarif_file: results.sarif
 
@@ -40,21 +40,15 @@ jobs:
     strategy:
       matrix:
         php:
-        - version: 7.4
-          coverage: false
-        - version: 8.0
-          coverage: false
-        - version: 8.1
-          coverage: false
-        - version: 8.2
-          coverage: false
         - version: 8.3
           coverage: true
         - version: 8.4
           coverage: false
+        - version: 8.5
+          coverage: false
         prefer-lowest: ['', '--prefer-lowest']
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
 
     - name: Install PHP
       uses: shivammathur/setup-php@v2
@@ -67,7 +61,7 @@ jobs:
 
     - name: Cache Composer packages
       id: composer-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: vendor
         key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
diff --git a/.gitignore b/.gitignore
index e16dfc7..5175100 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,7 @@
 !/tests/log/.gitkeep
 .phpunit.result.cache
 .phpcs-cache
+.phpunit.cache/
 phpunit.xml
-composer.lock
\ No newline at end of file
+composer.lock
+*.bak
diff --git a/composer.json b/composer.json
index fc06b27..0e501d9 100644
--- a/composer.json
+++ b/composer.json
@@ -1,36 +1,37 @@
 {
     "name": "fabiang/dateparser",
-    "description": "Parser for date strings",
+    "description": "Date parsing library supporting the full format RFC3339",
     "type": "library",
     "license": "BSD-2-Clause",
     "keywords": ["rfc3339", "dateparser", "date", "datetime", "parser"],
     "authors": [
         {
             "name": "Fabian Grutschus",
-            "email": "fabian.grutschus@invitel.de"
+            "email": "github@lubyte.de"
         }
     ],
     "minimum-stability": "stable",
     "require": {
-        "php": "^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
+        "php": "~8.3.0 || ~8.4.0 || ~8.5.0",
         "phplrt/runtime": "^3.2"
     },
+    "require-dev": {
+        "phpunit/phpunit": "^12.0",
+        "squizlabs/php_codesniffer": "*",
+        "vimeo/psalm": "*",
+        "laminas/laminas-coding-standard": "*",
+        "phplrt/compiler": "^3.2",
+        "mikey179/vfsstream": "^1.6.12"
+    },
     "autoload": {
         "psr-4": {
             "Fabiang\\Dateparser\\": "src/"
         }
     },
-    "require-dev": {
-        "phpunit/phpunit": "^9.5.16 || ^10.0",
-        "squizlabs/php_codesniffer": "^3.7",
-        "vimeo/psalm": "^4.23",
-        "laminas/laminas-coding-standard": "^2.3",
-        "phplrt/compiler": "^3.2"
-    },
     "scripts": {
-        "phpcs": "phpcs",
+        "phpcs": "phpcs --colors",
         "psalm": "psalm",
-        "phpunit": "phpunit",
+        "phpunit": "phpunit --colors --coverage-text",
         "test": [
             "@phpcs",
             "@psalm",
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 26e075e..56e7af9 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,26 +1,18 @@
-<phpunit
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
-    colors="true"
-    forceCoversAnnotation="true"
-    beStrictAboutChangesToGlobalState="true"
-    beStrictAboutOutputDuringTests="false"
-    beStrictAboutResourceUsageDuringSmallTests="true"
-    beStrictAboutTestsThatDoNotTestAnything="true"
-    beStrictAboutTodoAnnotatedTests="true">
-
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/12.5/phpunit.xsd" 
+    colors="true" 
+    beStrictAboutChangesToGlobalState="true" 
+    beStrictAboutOutputDuringTests="false" 
+    beStrictAboutTestsThatDoNotTestAnything="true" 
+    cacheDirectory=".phpunit.cache" 
+    requireCoverageMetadata="true">
     <testsuites>
         <testsuite name="unit">
             <directory>tests/src/</directory>
         </testsuite>
     </testsuites>
 
-    <coverage>
-        <include>
-            <directory>src/</directory>
-        </include>
-    </coverage>
-
     <php>
         <ini name="error_reporting" value="-1"/>
         <ini name="display_errors" value="On"/>
@@ -28,5 +20,11 @@
         <ini name="memory_limit" value="-1"/>
     </php>
 
-    <logging></logging>
+    <logging/>
+
+    <source>
+        <include>
+            <directory>src/</directory>
+        </include>
+    </source>
 </phpunit>
diff --git a/src/AbstractParser.php b/src/AbstractParser.php
index 419a4fc..1a8aa0f 100644
--- a/src/AbstractParser.php
+++ b/src/AbstractParser.php
@@ -5,6 +5,7 @@
 namespace Fabiang\Dateparser;
 
 use Fabiang\Dateparser\Exception\LoadDefinitionException;
+use Override;
 use Phplrt\Lexer\Lexer;
 use Phplrt\Lexer\Multistate;
 use Phplrt\Parser\BuilderInterface;
@@ -67,6 +68,7 @@ public function __construct(array $reducers)
                     /**
                      * {@inheritDoc}
                      */
+                    #[Override]
                     public function build(ContextInterface $context, $result)
                     {
                         $state = $context->getState();
diff --git a/src/Exception/UnexpectedValueException.php b/src/Exception/UnexpectedValueException.php
deleted file mode 100644
index 124e8a1..0000000
--- a/src/Exception/UnexpectedValueException.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Fabiang\Dateparser\Exception;
-
-use UnexpectedValueException as BaseUnexpectedValueException;
-
-/**
- * Generated at Tue, 25 Jul 2017 16:31:07 +0000 by fabian.grutschus
- */
-class UnexpectedValueException extends BaseUnexpectedValueException implements ExceptionInterface
-{
-}
diff --git a/src/ParserInterface.php b/src/ParserInterface.php
index fe22fa1..833de5e 100644
--- a/src/ParserInterface.php
+++ b/src/ParserInterface.php
@@ -6,6 +6,9 @@
 
 use DateTime;
 
+/**
+ * @psalm-api
+ */
 interface ParserInterface
 {
     public function parse(string $string): DateTime;
diff --git a/src/RFC3339.php b/src/RFC3339.php
index 2d62e95..056525b 100644
--- a/src/RFC3339.php
+++ b/src/RFC3339.php
@@ -5,10 +5,14 @@
 namespace Fabiang\Dateparser;
 
 use DateTime;
+use Override;
 
 use function sprintf;
 use function substr;
 
+/**
+ * @psalm-api
+ */
 class RFC3339 extends AbstractParser
 {
     public const T_YEAR              = 'T_YEAR';
@@ -25,6 +29,7 @@ class RFC3339 extends AbstractParser
     public const T_TIMEZONE_LEFT     = 'T_TIMEZONE_LEFT';
     public const T_TIMEZONE_RIGHT    = 'T_TIMEZONE_RIGHT';
 
+    #[Override]
     public function parse(string $string): DateTime
     {
         $parsedTokens = $this->baseParse('RFC3339', $string);
diff --git a/tests/src/AbstractParserTest.php b/tests/src/AbstractParserTest.php
new file mode 100644
index 0000000..fdef666
--- /dev/null
+++ b/tests/src/AbstractParserTest.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fabiang\Dateparser;
+
+use DateTime;
+use Fabiang\Dateparser\Exception\LoadDefinitionException;
+use org\bovigo\vfs\vfsStream;
+use Override;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+use function chmod;
+use function file_put_contents;
+
+#[CoversClass(AbstractParser::class)]
+final class AbstractParserTest extends TestCase
+{
+    public function testLoadFileMissing()
+    {
+        $this->expectException(LoadDefinitionException::class);
+        $this->expectExceptionMessageMatches('/^Unable to load definition file/');
+
+        $underTest = new class extends AbstractParser {
+            #[Override]
+            public function parse(string $string): DateTime
+            {
+                $this->load('UNKNOWN');
+            }
+        };
+        $underTest->parse('unrelevant');
+    }
+
+    public function testLoadNotReadable()
+    {
+        $this->expectException(LoadDefinitionException::class);
+        $this->expectExceptionMessageMatches('/^Definition file \'.*NOT_READABLE.php\' is not readable/');
+
+        $underTest = new class extends AbstractParser {
+            public function __construct()
+            {
+                $path = vfsStream::setup();
+                $file = $path->url() . '/NOT_READABLE.php';
+                file_put_contents($file, '<?php return [];');
+                chmod($file, 0000);
+                parent::__construct($path->url());
+            }
+
+            #[Override]
+            public function parse(string $string): DateTime
+            {
+                $this->load('NOT_READABLE');
+            }
+        };
+        $underTest->parse('unrelevant');
+    }
+}
diff --git a/tests/src/RFC3339Test.php b/tests/src/RFC3339Test.php
index 85cd121..838da1b 100644
--- a/tests/src/RFC3339Test.php
+++ b/tests/src/RFC3339Test.php
@@ -5,34 +5,25 @@
 namespace Fabiang\Dateparser;
 
 use DateTime;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 
 use function intval;
 
-/**
- * Generated by PHPUnit_SkeletonGenerator on 2017-07-25 at 17:34:16.
- *
- * @coversDefaultClass \Fabiang\Dateparser\RFC3339
- */
+#[CoversClass(RFC3339::class)]
+#[UsesClass(AbstractParser::class)]
 final class RFC3339Test extends TestCase
 {
     private RFC3339 $object;
 
-    /**
-     * Sets up the fixture, for example, opens a network connection.
-     * This method is called before a test is executed.
-     */
     protected function setUp(): void
     {
         $this->object = new RFC3339();
     }
 
-    /**
-     * @covers ::parse
-     * @covers ::getTimezoneValue
-     * @covers \Fabiang\Dateparser\AbstractParser
-     * @dataProvider provideValidDateStrings
-     */
+    #[DataProvider('provideValidDateStrings')]
     public function testParse(
         string $date,
         string $year,
@@ -56,7 +47,7 @@ public function testParse(
         $this->assertSame($microseconds, intval($dateObject->format('u')));
     }
 
-    public function provideValidDateStrings(): array
+    public static function provideValidDateStrings(): array
     {
         return [
             [