diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index d827aee..5e416b1 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -17,7 +17,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.4
           coverage: none
 
       - name: Get composer cache directory
@@ -52,7 +52,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           coverage: none
-          php-version: 8.2
+          php-version: 8.4
 
       - name: Get composer cache directory
         id: composer-cache
@@ -77,7 +77,7 @@ jobs:
 
     strategy:
       matrix:
-        php-versions: ['8.0', '8.1', '8.2']
+        php-versions: ['8.3', '8.4']
 
     steps:
       - name: Checkout code
@@ -104,7 +104,7 @@ jobs:
         run: composer install --no-interaction --no-progress --prefer-dist --optimize-autoloader
 
       - name: Run unit tests
-        run: ./vendor/bin/phpunit --verbose --coverage-clover build/logs/clover.xml --coverage-text
+        run: ./vendor/bin/phpunit
 
       - name: Publish coverage report to Codecov
         uses: codecov/codecov-action@v1
diff --git a/composer.json b/composer.json
index 8accd39..0b00533 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,7 @@
 {
     "name": "pauci/datetime",
     "description": "Enhanced DateTime, DateTimeImmutable and DateInterval objects",
+    "version": "0.7.0",
     "type": "library",
     "keywords": [
         "datetime",
@@ -22,7 +23,7 @@
         "issues": "https://github.com/pauci/datetime/issues"
     },
     "require": {
-        "php": "^8.0 || ^8.1 || ^8.2",
+        "php": "^8.3 || ^8.4",
         "ext-json": "*",
         "psr/clock": "^1.0"
     },
@@ -31,7 +32,8 @@
         "phpstan/extension-installer": "^1.2",
         "phpstan/phpstan": "^1.9",
         "phpstan/phpstan-phpunit": "^1.3",
-        "phpunit/phpunit": "^9.5",
+        "phpunit/phpunit": "^11.0.0",
+        "rector/rector": "^1.2",
         "squizlabs/php_codesniffer": "^3.7"
     },
     "suggest": {
@@ -57,12 +59,16 @@
         "check": [
             "@lint",
             "@cs-check",
+            "@rector",
             "@stan",
             "@test"
         ],
         "lint": "parallel-lint src tests",
         "cs-check": "phpcs",
         "cs-fix": "phpcbf",
+        "rector": "rector -n -vv",
+        "rector:clear": "rector -n --clear-cache -vv",
+        "rector:fix": "rector -vv",
         "stan": "phpstan analyse --no-progress",
         "test": "phpunit",
         "test-coverage": "phpunit --coverage-clover clover.xml"
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index a686948..ed19b24 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd" bootstrap="./tests/bootstrap.php" colors="true">
+<phpunit
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/11.5/phpunit.xsd"
+        bootstrap="./tests/bootstrap.php"
+        colors="true"
+>
   <coverage processUncoveredFiles="true">
     <include>
       <directory suffix=".php">./src</directory>
diff --git a/rector.php b/rector.php
new file mode 100644
index 0000000..8bfdc87
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodingStyle;
+use Rector\Config\RectorConfig;
+use Rector\Privatization;
+
+return RectorConfig::configure()
+    ->withPhpSets(php83: true)
+    ->withPaths([
+        __DIR__ . '/src',
+        __DIR__ . '/tests',
+    ]);
\ No newline at end of file
diff --git a/src/DateTime.php b/src/DateTime.php
index 24a0575..c3f536d 100644
--- a/src/DateTime.php
+++ b/src/DateTime.php
@@ -42,7 +42,7 @@ public static function now(): DateTimeInterface
     /**
      * @throws Exception
      */
-    public static function fromString(string $time, DateTimeZone $timezone = null): static
+    public static function fromString(string $time, ?DateTimeZone $timezone = null): static
     {
         $dateTime = parent::createFromInterface(new \DateTime($time, $timezone));
         \assert($dateTime instanceof static);
@@ -53,7 +53,7 @@ public static function fromString(string $time, DateTimeZone $timezone = null):
     /**
      * @throws Exception
      */
-    public static function fromTimestamp(int $timestamp, DateTimeZone $timezone = null): static
+    public static function fromTimestamp(int $timestamp, ?DateTimeZone $timezone = null): static
     {
         $dateTime = static::createFromFormat('U', (string) $timestamp);
         \assert(false !== $dateTime);
@@ -63,7 +63,7 @@ public static function fromTimestamp(int $timestamp, DateTimeZone $timezone = nu
             : $dateTime->inDefaultTimezone();
     }
 
-    public static function fromFloatTimestamp(float $timestamp, DateTimeZone $timezone = null): static
+    public static function fromFloatTimestamp(float $timestamp, ?DateTimeZone $timezone = null): static
     {
         $integer = floor($timestamp);
         $fract = fmod($timestamp, 1);
@@ -80,21 +80,24 @@ public static function fromFloatTimestamp(float $timestamp, DateTimeZone $timezo
     }
 
     #[\ReturnTypeWillChange]
+    #[\Override]
     public static function createFromFormat(
         string $format,
         string $datetime,
-        DateTimeZone $timezone = null
+        ?DateTimeZone $timezone = null
     ): static|false {
         return parent::createFromFormat($format, $datetime, $timezone);
     }
 
     #[\ReturnTypeWillChange]
+    #[\Override]
     public static function createFromMutable(\DateTime $object): static
     {
         return parent::createFromMutable($object);
     }
 
     #[\ReturnTypeWillChange]
+    #[\Override]
     public static function createFromInterface(\DateTimeInterface $object): static
     {
         $dateTime = parent::createFromInterface($object);
@@ -106,6 +109,7 @@ public static function createFromInterface(\DateTimeInterface $object): static
     /**
      * @throws Exception
      */
+    #[\Override]
     public function diff(\DateTimeInterface $targetObject, bool $absolute = false): DateInterval
     {
         return DateInterval::fromDateInterval(
@@ -113,56 +117,67 @@ public function diff(\DateTimeInterface $targetObject, bool $absolute = false):
         );
     }
 
+    #[\Override]
     public function add(\DateInterval $interval): static
     {
         return parent::add($interval);
     }
 
+    #[\Override]
     public function sub(\DateInterval $interval): static
     {
         return parent::sub($interval);
     }
 
+    #[\Override]
     public function modify(string $modifier): static|false
     {
         return parent::modify($modifier);
     }
 
+    #[\Override]
     public function setDate(int $year, int $month, int $day): static
     {
         return parent::setDate($year, $month, $day);
     }
 
+    #[\Override]
     public function setISODate(int $year, int $week, int $dayOfWeek = 1): static
     {
         return parent::setISODate($year, $week, $dayOfWeek);
     }
 
+    #[\Override]
     public function setTime(int $hour, int $minute, int $second = 0, int $microsecond = 0): static
     {
         return parent::setTime($hour, $minute, $second, $microsecond);
     }
 
+    #[\Override]
     public function setTimestamp(int $timestamp): static
     {
         return parent::setTimestamp($timestamp);
     }
 
+    #[\Override]
     public function setTimezone(\DateTimeZone $timezone): static
     {
         return parent::setTimezone($timezone);
     }
 
+    #[\Override]
     public function equals(DateTimeInterface $dateTime): bool
     {
         return $this == $dateTime;
     }
 
+    #[\Override]
     public function inDefaultTimezone(): static
     {
         return $this->setTimezone(new DateTimeZone(date_default_timezone_get()));
     }
 
+    #[\Override]
     public function toString(): string
     {
         $format = static::$format
@@ -175,11 +190,13 @@ public function toString(): string
         return $this->format($format);
     }
 
+    #[\Override]
     public function __toString(): string
     {
         return $this->toString();
     }
 
+    #[\Override]
     public function jsonSerialize(): string
     {
         return $this->toString();
diff --git a/src/FrozenClock.php b/src/FrozenClock.php
index 97ecfb0..234ca11 100644
--- a/src/FrozenClock.php
+++ b/src/FrozenClock.php
@@ -6,11 +6,8 @@
 
 class FrozenClock implements ClockInterface
 {
-    private DateTime $now;
-
-    public function __construct(DateTime $now = null)
+    public function __construct(private DateTime $now = new DateTime())
     {
-        $this->now = $now ?? new DateTime();
     }
 
     public function set(DateTime $now): void
@@ -26,6 +23,7 @@ public function modify(string $modifier): void
         $this->now = $now;
     }
 
+    #[\Override]
     public function now(): DateTime
     {
         return $this->now;
diff --git a/tests/src/DateTimeTest.php b/tests/src/DateTimeTest.php
index d5fe41b..31d144f 100644
--- a/tests/src/DateTimeTest.php
+++ b/tests/src/DateTimeTest.php
@@ -189,10 +189,10 @@ public function testModify(): void
 
     public function testModifyFailed(): void
     {
-        $this->expectError();
-        $this->expectErrorMessage('DateTimeImmutable::modify(): Failed to parse time string (foo) at position 0 (f): The timezone could not be found in the database');
+        self::expectExceptionMessage('Failed to parse time string (foo) at position 0 (f): The timezone could not be found in the database');
 
         $dateTime = DateTime::fromString('2016-05-12 22:37:46+02:00');
+
         $dateTime->modify('foo');
     }
 
diff --git a/tests/src/FrozenClockTest.php b/tests/src/FrozenClockTest.php
index 1692c28..422f206 100644
--- a/tests/src/FrozenClockTest.php
+++ b/tests/src/FrozenClockTest.php
@@ -51,8 +51,7 @@ public function testItFailsToModify(): void
     {
         $clock = new FrozenClock();
 
-        $this->expectError();
-        $this->expectErrorMessage('DateTimeImmutable::modify(): Failed to parse time string (foo) at position 0 (f): The timezone could not be found in the database');
+        self::expectExceptionMessage('DateTimeImmutable::modify(): Failed to parse time string (foo) at position 0 (f): The timezone could not be found in the database');
 
         $clock->modify('foo');
     }