diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index c9d0a2f..9e4c2ee 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -6,10 +6,3 @@ updates:
     interval: monthly
   open-pull-requests-limit: 10
   versioning-strategy: increase
-  ignore:
-  - dependency-name: symfony/polyfill-php80
-    versions:
-    - 1.22.0
-  - dependency-name: phpunit/phpunit
-    versions:
-    - 8.5.14
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 171ca1e..63bf993 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [7.2, 7.3, 7.4, 8.0]
+        php: [7.3, 7.4, 8.0]
         experimental: [false]
         include:
           - php: 8.0
@@ -37,7 +37,7 @@ jobs:
 
       - name: Static analysis
         if: matrix.analysis
-        run: vendor/bin/phpstan analyse src
+        run: vendor/bin/phpstan
 
       - name: Tests
         run: vendor/bin/phpunit --coverage-clover clover.xml
@@ -47,5 +47,5 @@ jobs:
         env:
           COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          composer require php-coveralls/php-coveralls -n
+          composer require php-coveralls/php-coveralls -n -W
           vendor/bin/php-coveralls --coverage_clover=clover.xml -v
diff --git a/README.md b/README.md
index 3afbb9d..3c2a5f0 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@ $ composer require slim/psr7
 ```
 
 This will install the `slim/psr7` component and all required dependencies.
-PHP 7.2 or newer is required.
+PHP 7.3 or newer is required.
 
 ## Tests
 
diff --git a/composer.json b/composer.json
index f94ecef..816775f 100644
--- a/composer.json
+++ b/composer.json
@@ -28,11 +28,11 @@
     }
   ],
   "require": {
-    "php": "^7.2 || ^8.0",
+    "php": "^7.3 || ^8.0",
     "fig/http-message-util": "^1.1.5",
     "psr/http-factory": "^1.0",
     "psr/http-message": "^1.0",
-    "ralouphie/getallheaders": "^3",
+    "ralouphie/getallheaders": "^3.0",
     "symfony/polyfill-php80": "^1.23"
   },
   "require-dev": {
@@ -40,10 +40,11 @@
     "adriansuter/php-autoload-override": "^1.2",
     "http-interop/http-factory-tests": "^0.9.0",
     "php-http/psr7-integration-tests": "dev-master",
-    "phpstan/phpstan": "^0.12",
-    "phpunit/phpunit": "^8.5 || ^9.5",
-    "squizlabs/php_codesniffer": "^3.6",
-    "weirdan/prophecy-shim": "^1.0 || ^2.0.2"
+    "phpspec/prophecy": "^1.14",
+    "phpspec/prophecy-phpunit": "^2.0",
+    "phpstan/phpstan": "^0.12.99",
+    "phpunit/phpunit": "^9.5",
+    "squizlabs/php_codesniffer": "^3.6"
   },
   "provide": {
     "psr/http-message-implementation": "1.0",
@@ -67,7 +68,7 @@
     ],
     "phpunit": "phpunit",
     "phpcs": "phpcs",
-    "phpstan": "phpstan analyse src --memory-limit=-1"
+    "phpstan": "phpstan --memory-limit=-1"
   },
   "config": {
     "sort-packages": true
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 4ae0e40..ccac1b2 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,3 +1,5 @@
 parameters:
   level: max
   checkMissingIterableValueType: false
+  paths:
+    - src
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index f3bfd90..a65dc57 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,38 +1,23 @@
 <?xml version="1.0" encoding="UTF-8"?>
-
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/8.5/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
          backupGlobals="true"
-         backupStaticAttributes="false"
-         beStrictAboutTestsThatDoNotTestAnything="true"
-         beStrictAboutChangesToGlobalState="false"
          beStrictAboutOutputDuringTests="true"
          colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false"
          bootstrap="tests/bootstrap.php"
 >
     <testsuites>
         <testsuite name="Slim-Psr7 Test Suite">
-            <directory>./tests/</directory>
+            <directory>tests</directory>
         </testsuite>
     </testsuites>
 
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">src/</directory>
-        </whitelist>
-    </filter>
-
-    <logging>
-        <log
-            type="coverage-html"
-            target="./coverage"
-            lowUpperBound="20"
-            highLowerBound="50"
-        />
-    </logging>
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+        <report>
+            <html outputDirectory="coverage" lowUpperBound="20" highLowerBound="50"/>
+        </report>
+    </coverage>
 </phpunit>
diff --git a/tests/Assets/PhpFactoryFunctionOverrides.php b/tests/Assets/PhpFactoryFunctionOverrides.php
deleted file mode 100644
index 1bef58d..0000000
--- a/tests/Assets/PhpFactoryFunctionOverrides.php
+++ /dev/null
@@ -1,45 +0,0 @@
-<?php
-
-/**
- * Slim Framework (https://slimframework.com)
- *
- * @license https://github.com/slimphp/Slim-Psr7/blob/master/LICENSE.md (MIT License)
- */
-
-declare(strict_types=1);
-
-namespace Slim\Psr7\Factory;
-
-/**
- * Return `false` if the parameter is "non-readable", otherwise the function would return the value from
- * the php built-in function.
- *
- * @param string $filename
- *
- * @return bool
- */
-function is_readable(string $filename): bool
-{
-    if ($filename === 'non-readable') {
-        return false;
-    }
-
-    return \is_readable($filename);
-}
-
-/**
- * Return global set value if set or value from php built-in function.
- *
- * @param $filename
- * @param $mode
- *
- * @return bool|resource
- */
-function fopen($filename, $mode)
-{
-    if (isset($GLOBALS['fopen_return'])) {
-        return isset($GLOBALS['fopen_return']);
-    }
-
-    return \fopen($filename, $mode);
-}
diff --git a/tests/Assets/PhpFunctionOverrides.php b/tests/Assets/PhpFunctionOverrides.php
deleted file mode 100644
index ebefc44..0000000
--- a/tests/Assets/PhpFunctionOverrides.php
+++ /dev/null
@@ -1,126 +0,0 @@
-<?php
-
-/**
- * Slim Framework (https://slimframework.com)
- *
- * @license https://github.com/slimphp/Slim-Psr7/blob/master/LICENSE.md (MIT License)
- */
-
-declare(strict_types=1);
-
-namespace Slim\Psr7;
-
-use Slim\Tests\Psr7\Assets\HeaderStack;
-
-use function array_key_exists;
-
-/**
- * Return the value of the global variable $GLOBALS['getallheaders_return'] if it exists. Otherwise the
- * function override calls the default php built-in function.
- *
- * @return array|false
- */
-function getallheaders()
-{
-    if (array_key_exists('getallheaders_return', $GLOBALS)) {
-        return $GLOBALS['getallheaders_return'];
-    }
-
-    return \getallheaders();
-}
-
-/**
- * Emit a header, without creating actual output artifacts
- *
- * @param string   $string
- * @param bool     $replace
- * @param int|null $statusCode
- */
-function header($string, $replace = true, $statusCode = null)
-{
-    HeaderStack::push(
-        [
-            'header'      => $string,
-            'replace'     => $replace,
-            'status_code' => $statusCode,
-        ]
-    );
-}
-
-/**
- * Remove a previously emmited header from the HeaderStack.
- *
- * @param string|null $name
- */
-function header_remove($name = null)
-{
-    HeaderStack::remove($name);
-}
-
-/**
- * @param string $filename
- *
- * @return bool
- */
-function is_uploaded_file(string $filename): bool
-{
-    if (isset($GLOBALS['is_uploaded_file_return'])) {
-        return $GLOBALS['is_uploaded_file_return'];
-    }
-
-    return \is_uploaded_file($filename);
-}
-
-/**
- * Return the level of the output buffering shifted by the value of the global
- * variable $GLOBALS['ob_get_level_shift'] if it exists. Otherwise the function
- * override calls the default php built-in function.
- *
- * @return int
- */
-function ob_get_level(): int
-{
-    if (isset($GLOBALS['ob_get_level_shift'])) {
-        return \ob_get_level() + $GLOBALS['ob_get_level_shift'];
-    }
-
-    return \ob_get_level();
-}
-
-/**
- * @param string        $source
- * @param string        $destination
- * @param resource|null $context
- *
- * @return bool
- */
-function copy(string $source, string $destination, $context = null): bool
-{
-    if (isset($GLOBALS['copy_return'])) {
-        return $GLOBALS['copy_return'];
-    }
-
-    if ($context === null) {
-        return \copy($source, $destination);
-    }
-    return \copy($source, $destination, $context);
-}
-
-/**
- * @param string        $oldName
- * @param string        $newName
- * @param resource|null $context
- *
- * @return bool
- */
-function rename(string $oldName, string $newName, $context = null): bool
-{
-    if (isset($GLOBALS['rename_return'])) {
-        return $GLOBALS['rename_return'];
-    }
-
-    if ($context === null) {
-        return \rename($oldName, $newName);
-    }
-    return \rename($oldName, $newName, $context = null);
-}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 88d5fb4..dbe4a90 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -18,9 +18,6 @@
 
 $classLoader = require __DIR__ . '/../vendor/autoload.php';
 
-//require __DIR__ . '/Assets/PhpFunctionOverrides.php';
-//require __DIR__ . '/Assets/PhpFactoryFunctionOverrides.php';
-
 Override::apply($classLoader, [
     Headers::class => [
         'getallheaders' => function () {