diff --git a/.gitignore b/.gitignore
index 82cfc4e..6c0453b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 .idea
 composer.lock
 vendor
+.phpunit.result.cache
+phpunit.xml.dist.bak
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9286e30..19dc1fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Changeed
 
+## [2.1.0](https://github.com/bazzline/php_component_cli_argument/tree/2.1.0) - released at 2022-11-23
+
+### Changeed
+
+* Raised minimum php version requirement from `7.0` to `8.0`
+* Updated development requirement from phpunit 6.0 to 8.0
+* Migrated phpunit xml
+* Migrated code base to php 8.0
+
 ## [2.0.0](https://github.com/bazzline/php_component_cli_argument/tree/2.0.0) - released at 2018-01-12
 
 ### Changed
diff --git a/Example/run.php b/Example/run.php
index e1c606f..c9c239e 100644
--- a/Example/run.php
+++ b/Example/run.php
@@ -4,9 +4,11 @@
  * @since: 2015-04-16
  */
 
+use Net\Bazzline\Component\Cli\Arguments\Arguments;
+
 require_once __DIR__ . '/../vendor/autoload.php';
 
-$arguments = new \Net\Bazzline\Component\Cli\Arguments\Arguments($argv);
+$arguments = new Arguments($argv);
 
 if ($arguments->hasArguments()) {
     echo $arguments->getNumberOfArguments() . ' arguments provided:' . PHP_EOL;
diff --git a/composer.json b/composer.json
index b96ec55..4391e9d 100644
--- a/composer.json
+++ b/composer.json
@@ -18,10 +18,10 @@
     "type": "library",
     "minimum-stability": "dev",
     "require": {
-        "php": "~7.0"
+        "php": "~8.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.0"
+        "phpunit/phpunit": "~9.0"
     },
     "license": "LGPL-3.0-only",
     "authors": [
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 13323cf..ece9c20 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,17 +1,9 @@
-<phpunit bootstrap="test/bootstrap.php"
-         cacheTokens="false"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         stopOnError="false"
-         stopOnFailure="false"
-         stopOnIncomplete="false"
-         stopOnSkipped="false">
-
-    <testsuites>
-        <testsuite name="Test Suite">
-            <directory>test/</directory>
-        </testsuite>
-    </testsuites>
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="test/bootstrap.php" colors="true" convertErrorsToExceptions="true" convertNoticesToExceptions="true" convertWarningsToExceptions="true" stopOnError="false" stopOnFailure="false" stopOnIncomplete="false" stopOnSkipped="false" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage/>
+  <testsuites>
+    <testsuite name="Test Suite">
+      <directory>test/</directory>
+    </testsuite>
+  </testsuites>
 </phpunit>
diff --git a/source/Arguments.php b/source/Arguments.php
index 2153dc1..3e8f4ac 100644
--- a/source/Arguments.php
+++ b/source/Arguments.php
@@ -8,26 +8,13 @@
 
 class Arguments
 {
-    /** @var array */
-    private $arguments;
+    private array $arguments;
+    private array $flags;
+    private array $lists;
+    private Parser $parser;
+    private array $values;
 
-    /** @var array */
-    private $flags;
-
-    /** @var array */
-    private $lists;
-
-    /** @var Parser */
-    private $parser;
-
-    /** @var array */
-    private $values;
-
-    /**
-     * @param null|array $argv
-     * @param boolean $removeFirstArgument
-     */
-    public function __construct($argv = null, $removeFirstArgument = true)
+    public function __construct(array $argv = null, bool $removeFirstArgument = true)
     {
         $this->parser = new Parser();
 
@@ -38,137 +25,84 @@ public function __construct($argv = null, $removeFirstArgument = true)
         }
     }
 
-    /**
-     * @return array
-     */
-    public function getArguments()
+    public function getArguments(): array
     {
         return $this->arguments;
     }
 
-    /**
-     * @return array
-     */
-    public function getFlags()
+    public function getFlags(): array
     {
         return $this->flags;
     }
 
-    /**
-     * @param string $name
-     * @return null|array
-     */
-    public function getList($name)
+    public function getList(string $name): null|array
     {
         return (isset($this->lists[$name]))
             ? $this->lists[$name]
             : null;
     }
 
-    /**
-     * @return int
-     */
-    public function getNumberOfArguments()
+    public function getNumberOfArguments(): int
     {
         return (count($this->arguments));
     }
 
-    /**
-     * @return int
-     */
-    public function getNumberOfFlags()
+    public function getNumberOfFlags(): int
     {
         return (count($this->flags));
     }
 
-    /**
-     * @return int
-     */
-    public function getNumberOfLists()
+    public function getNumberOfLists(): int
     {
         return (count($this->lists));
     }
 
-    /**
-     * @return int
-     */
-    public function getNumberOfValues()
+    public function getNumberOfValues(): int
     {
         return (count($this->values));
     }
 
-    /**
-     * @return array
-     */
-    public function getLists()
+    public function getLists(): array
     {
         return $this->lists;
     }
 
-    /**
-     * @return array
-     */
-    public function getValues()
+    public function getValues(): array
     {
         return $this->values;
     }
 
-    /**
-     * @return bool
-     */
-    public function hasArguments()
+    public function hasArguments(): bool
     {
         return (!empty($this->arguments));
     }
 
-    /**
-     * @param string $name
-     * @return bool
-     */
-    public function hasFlag($name)
+    public function hasFlag(string $name): bool
     {
         return (in_array($name, $this->flags));
     }
 
-    /**
-     * @return bool
-     */
-    public function hasFlags()
+    public function hasFlags(): bool
     {
         return (!empty($this->flags));
     }
 
-    /**
-     * @param string $name
-     * @return bool
-     */
-    public function hasList($name)
+    public function hasList(string $name): bool
     {
         return (isset($this->lists[$name]));
     }
 
-    /**
-     * @return bool
-     */
-    public function hasLists()
+    public function hasLists(): bool
     {
         return (!empty($this->lists));
     }
 
-    /**
-     * @return bool
-     */
-    public function hasValues()
+    public function hasValues(): bool
     {
         return (!empty($this->values));
     }
 
-    /**
-     * @param array $argv
-     * @param boolean $removeFirstArgument
-     * @return $this
-     */
-    public function parseArguments(array $argv, $removeFirstArgument = true)
+    public function parseArguments(array $argv, bool $removeFirstArgument = true): self
     {
         if ($removeFirstArgument) {
             array_shift($argv);
@@ -181,34 +115,22 @@ public function parseArguments(array $argv, $removeFirstArgument = true)
         return $this;
     }
 
-    /**
-     * @return array
-     */
-    public function convertToArray()
+    public function convertToArray(): array
     {
         return $this->getArguments();
     }
 
-    /**
-     * @return string
-     */
-    public function convertToString()
+    public function convertToString(): string
     {
         return implode(' ', $this->convertToArray());
     }
 
-    /**
-     * @return string
-     */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->convertToString();
     }
 
-    /**
-     * @param Parser $parser
-     */
-    private function setArgumentsFromParser(Parser $parser)
+    private function setArgumentsFromParser(Parser $parser): void
     {
         $this->flags    = $parser->getFlags();
         $this->lists    = $parser->getLists();
diff --git a/source/Parser.php b/source/Parser.php
index f544cc0..0db9a1a 100644
--- a/source/Parser.php
+++ b/source/Parser.php
@@ -7,24 +7,16 @@
 
 class Parser
 {
-    /** @var array */
-    private $flags;
-
-    /** @var array */
-    private $lists;
-
-    /** @var array */
-    private $values;
+    private array $flags;
+    private array $lists;
+    private array $values;
 
     public function __construct()
     {
         $this->initiate();
     }
 
-    /**
-     * @param array $arguments
-     */
-    public function parse(array $arguments)
+    public function parse(array $arguments): void
     {
         $this->initiate();
 
@@ -33,65 +25,43 @@ public function parse(array $arguments)
         }
     }
 
-    /**
-     * @return array
-     */
-    public function getFlags()
+    public function getFlags(): array
     {
         return $this->flags;
     }
 
-    /**
-     * @return array
-     */
-    public function getLists()
+    public function getLists(): array
     {
         return $this->lists;
     }
 
-    /**
-     * @return array
-     */
-    public function getValues()
+    public function getValues(): array
     {
         return $this->values;
     }
 
-    /**
-     * @param string $name
-     * @param mixed $value
-     */
-    private function addToList($name, $value)
+    private function addToList(string $name, mixed $value): void
     {
         $value = trim($value, '"'); //remove >"< if exists
 
-        if (isset($this->lists[$name])) {
-            $collection = $this->lists[$name];
-        } else {
-            $collection = [];
-        }
+        $collection = $this->lists[$name] ?? [];
 
         $collection[]       = $value;
         $this->lists[$name] = $collection;
     }
 
-    /**
-     * @param string $string
-     * @param string $search
-     * @return bool
-     */
-    private function contains($string, $search)
+    private function contains(string $string, string $search): bool
     {
         if (strlen($search) === 0) {
             $contains = false;
         } else {
-            $contains = !(strpos($string, $search) === false);
+            $contains = !(!str_contains($string, $search));
         }
 
         return $contains;
     }
 
-    private function handleLongNameListOrFlag($argument)
+    private function handleLongNameListOrFlag(string $argument): void
     {
         if ($this->contains($argument, '=')) {
             $position   = strpos($argument, '=');
@@ -103,7 +73,7 @@ private function handleLongNameListOrFlag($argument)
         }
     }
 
-    private function handleShortNameListOrFlag($argument)
+    private function handleShortNameListOrFlag(string $argument): void
     {
         $containsEqualCharacter             = ($this->contains($argument, '='));
         $equalCharacterIsOnSecondPosition   = (strpos($argument, '=') === 1);
@@ -118,23 +88,20 @@ private function handleShortNameListOrFlag($argument)
             $length = strlen($argument);
             $iterator = 0;
             while ($iterator < $length) {
-                $this->flags[] = $argument{$iterator};
+                $this->flags[] = $argument[$iterator];
                 ++$iterator;
             }
         }
     }
 
-    private function initiate()
+    private function initiate(): void
     {
         $this->flags    = [];
         $this->lists    = [];
         $this->values   = [];
     }
 
-    /**
-     * @param $argument
-     */
-    private function addToFittingCollection($argument)
+    private function addToFittingCollection(string $argument): void
     {
         if ($this->hasLengthOf($argument, 1)) {
             $this->values[] = $argument;
@@ -149,26 +116,15 @@ private function addToFittingCollection($argument)
         }
     }
 
-    /**
-     * @param string $string
-     * @param string $start
-     * @return bool
-     */
-    private function startsWith($string, $start)
+    private function startsWith(string $string, string $start): bool
     {
         return (strncmp($string, $start, strlen($start)) === 0);
     }
 
-    /**
-     * @param string $string
-     * @param int $expectedLength
-     * @return bool
-     */
-    private function hasLengthOf($string, $expectedLength)
+    private function hasLengthOf(string $string, int $expectedLength): bool
     {
-        $length         = strlen($string);
-        $hasLengthOf    = ($length == $expectedLength);
+        $length = strlen($string);
 
-        return $hasLengthOf;
+        return ($length == $expectedLength);
     }
 }