diff --git a/.gitignore b/.gitignore
index da52ddb..f1c2f91 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 .DS_Store
 .idea
+.phpunit.result.cache
 composer.lock
 coverage
 docs/_site
diff --git a/.travis.yml b/.travis.yml
index 49b6f55..8fe1742 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,11 +4,14 @@ dist: trusty
 
 matrix:
   include:
-    - php: 7.1
     - php: 7.2
     - php: 7.3
     - php: 7.4
       env: ANALYSIS='true'
+    - php: nightly
+
+  allow_failures:
+    - php: nightly
 
 before_script:
   - if [[ "$ANALYSIS" == 'true' ]]; then composer require php-coveralls/php-coveralls:^2.2.0 ; fi
diff --git a/README.md b/README.md
index c527fa6..4045833 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ only.**
 
 ## Requirements 
 
-- PHP 7.1 or later
+- PHP 7.2 or later
 - Composer with PSR-4 (PSR-0 is not supported)
 
 
diff --git a/composer.json b/composer.json
index 34d361e..0440171 100644
--- a/composer.json
+++ b/composer.json
@@ -34,12 +34,12 @@
     ]
   },
   "require": {
-    "php": "^7.1",
+    "php": "^7.2 || ^8.0",
     "nikic/php-parser": "^4.4"
   },
   "require-dev": {
     "phpstan/phpstan": "^0.12.25",
-    "phpunit/phpunit": "^7.5",
+    "phpunit/phpunit": "^8.5",
     "squizlabs/php_codesniffer": "^3.5"
   },
   "scripts": {
diff --git a/docs/index.md b/docs/index.md
index 1428507..06b4e4c 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -11,7 +11,7 @@ only.**
 
 # Requirements
 
-- PHP 7.1 or later
+- PHP 7.2 or later
 - Composer with PSR-4 (PSR-0 is not supported)
 
 
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9a450c6..5f44a59 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/7.1/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/8.5/phpunit.xsd"
          backupGlobals="true"
          beStrictAboutOutputDuringTests="true"
          colors="true"
diff --git a/tests/AbstractIntegrationTest.php b/tests/AbstractIntegrationTest.php
index 8b227c7..0867dc1 100644
--- a/tests/AbstractIntegrationTest.php
+++ b/tests/AbstractIntegrationTest.php
@@ -19,12 +19,12 @@ abstract class AbstractIntegrationTest extends TestCase
 
     private static $classLoader;
 
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
     {
         self::$classLoader = require(__DIR__ . '/../vendor/autoload.php');
     }
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (!$this->overrideApplied) {
diff --git a/tests/FileStreamWrapperTest.php b/tests/FileStreamWrapperTest.php
index 3080f74..80e9ee0 100644
--- a/tests/FileStreamWrapperTest.php
+++ b/tests/FileStreamWrapperTest.php
@@ -22,7 +22,7 @@ final class FileStreamWrapperTest extends TestCase
      */
     private $tempFilePath;
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         // Make sure that we restore the default file stream wrapper.
         \stream_wrapper_restore('file');
diff --git a/tests/IntegrationCustomNamespaceTest.php b/tests/IntegrationCustomNamespaceTest.php
index 828ca13..1ee4400 100644
--- a/tests/IntegrationCustomNamespaceTest.php
+++ b/tests/IntegrationCustomNamespaceTest.php
@@ -12,7 +12,7 @@
 
 class IntegrationCustomNamespaceTest extends AbstractIntegrationTest
 {
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
     {
         require_once(__DIR__ . '/assets/PHPCustomAutoloadOverride.php');
     }
diff --git a/tests/IntegrationNamespaceTest.php b/tests/IntegrationNamespaceTest.php
index f0ef0f0..f947496 100644
--- a/tests/IntegrationNamespaceTest.php
+++ b/tests/IntegrationNamespaceTest.php
@@ -12,7 +12,7 @@
 
 class IntegrationNamespaceTest extends AbstractIntegrationTest
 {
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
     {
         require_once(__DIR__ . '/assets/PHPAutoloadOverride.php');
     }