diff --git a/composer.json b/composer.json
index 756c0f4c..9d3cd9a5 100644
--- a/composer.json
+++ b/composer.json
@@ -29,7 +29,7 @@
 		"yzalis/identicon" : "^2.0.0"
 	},
 	"require-dev" : {
-		"phpunit/phpunit" : "^4.6 || ^5 || ^9"
+		"phpunit/phpunit" : "^5 || ^9"
 	},
 	"autoload" : {
 		"psr-4" : {
diff --git a/composer.lock b/composer.lock
index 4a680dbb..7149b7e7 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "a0e6ddfb640e9d613dfb4bddd578cc94",
+    "content-hash": "c5e5c4d3d99ae93c94cc75e225aa50f5",
     "packages": [
         {
             "name": "paragonie/random_compat",
diff --git a/tst/ConfigurationTest.php b/tst/ConfigurationTest.php
index bb4ce36f..d52027a3 100644
--- a/tst/ConfigurationTest.php
+++ b/tst/ConfigurationTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Configuration;
 
-class ConfigurationTest extends PHPUnit_Framework_TestCase
+class ConfigurationTest extends TestCase
 {
     private $_minimalConfig;
 
diff --git a/tst/ConfigurationTestGenerator.php b/tst/ConfigurationTestGenerator.php
index 284fa5f2..098fae7f 100755
--- a/tst/ConfigurationTestGenerator.php
+++ b/tst/ConfigurationTestGenerator.php
@@ -408,13 +408,14 @@ class ConfigurationTestGenerator
  * DO NOT EDIT: This file is generated automatically using configGenerator.php
  */
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Controller;
 use PrivateBin\Data\Filesystem;
 use PrivateBin\Persistence\ServerSalt;
 use PrivateBin\Persistence\TrafficLimiter;
 use PrivateBin\Request;
 
-class ConfigurationCombinationsTest extends PHPUnit_Framework_TestCase
+class ConfigurationCombinationsTest extends TestCase
 {
     private $_conf;
 
diff --git a/tst/ControllerTest.php b/tst/ControllerTest.php
index b00f2ce6..43556448 100644
--- a/tst/ControllerTest.php
+++ b/tst/ControllerTest.php
@@ -1,12 +1,13 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Controller;
 use PrivateBin\Data\Filesystem;
 use PrivateBin\Persistence\ServerSalt;
 use PrivateBin\Persistence\TrafficLimiter;
 use PrivateBin\Request;
 
-class ControllerTest extends PHPUnit_Framework_TestCase
+class ControllerTest extends TestCase
 {
     protected $_data;
 
diff --git a/tst/ControllerWithDbTest.php b/tst/ControllerWithDbTest.php
index 90dee920..cfa08172 100644
--- a/tst/ControllerWithDbTest.php
+++ b/tst/ControllerWithDbTest.php
@@ -1,5 +1,6 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Data\Database;
 
 require_once 'ControllerTest.php';
diff --git a/tst/Data/DatabaseTest.php b/tst/Data/DatabaseTest.php
index 0d48eb6a..24bbfa7b 100644
--- a/tst/Data/DatabaseTest.php
+++ b/tst/Data/DatabaseTest.php
@@ -1,9 +1,10 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Controller;
 use PrivateBin\Data\Database;
 
-class DatabaseTest extends PHPUnit_Framework_TestCase
+class DatabaseTest extends TestCase
 {
     private $_model;
 
diff --git a/tst/Data/FilesystemTest.php b/tst/Data/FilesystemTest.php
index 37e03f36..1961a813 100644
--- a/tst/Data/FilesystemTest.php
+++ b/tst/Data/FilesystemTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Data\Filesystem;
 
-class FilesystemTest extends PHPUnit_Framework_TestCase
+class FilesystemTest extends TestCase
 {
     private $_model;
 
diff --git a/tst/FilterTest.php b/tst/FilterTest.php
index 284802f0..df9581b4 100644
--- a/tst/FilterTest.php
+++ b/tst/FilterTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Filter;
 
-class FilterTest extends PHPUnit_Framework_TestCase
+class FilterTest extends TestCase
 {
     public function testFilterMakesTimesHumanlyReadable()
     {
diff --git a/tst/FormatV2Test.php b/tst/FormatV2Test.php
index 8aa4d3ca..8b8b6b82 100644
--- a/tst/FormatV2Test.php
+++ b/tst/FormatV2Test.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\FormatV2;
 
-class FormatV2Test extends PHPUnit_Framework_TestCase
+class FormatV2Test extends TestCase
 {
     public function testFormatV2ValidatorValidatesCorrectly()
     {
diff --git a/tst/I18nTest.php b/tst/I18nTest.php
index 7d549baa..c527ac57 100644
--- a/tst/I18nTest.php
+++ b/tst/I18nTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\I18n;
 
-class I18nTest extends PHPUnit_Framework_TestCase
+class I18nTest extends TestCase
 {
     private $_translations = array();
 
diff --git a/tst/JsonApiTest.php b/tst/JsonApiTest.php
index 9655e609..4173b384 100644
--- a/tst/JsonApiTest.php
+++ b/tst/JsonApiTest.php
@@ -1,11 +1,12 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Controller;
 use PrivateBin\Data\Filesystem;
 use PrivateBin\Persistence\ServerSalt;
 use PrivateBin\Request;
 
-class JsonApiTest extends PHPUnit_Framework_TestCase
+class JsonApiTest extends TestCase
 {
     protected $_model;
 
diff --git a/tst/ModelTest.php b/tst/ModelTest.php
index d5c4074f..4fbbb5b9 100644
--- a/tst/ModelTest.php
+++ b/tst/ModelTest.php
@@ -1,6 +1,7 @@
 <?php
 
 use Identicon\Identicon;
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Configuration;
 use PrivateBin\Data\Database;
 use PrivateBin\Model;
@@ -10,7 +11,7 @@ use PrivateBin\Persistence\ServerSalt;
 use PrivateBin\Persistence\TrafficLimiter;
 use PrivateBin\Vizhash16x16;
 
-class ModelTest extends PHPUnit_Framework_TestCase
+class ModelTest extends TestCase
 {
     private $_conf;
 
diff --git a/tst/Persistence/PurgeLimiterTest.php b/tst/Persistence/PurgeLimiterTest.php
index 391a840b..68bac020 100644
--- a/tst/Persistence/PurgeLimiterTest.php
+++ b/tst/Persistence/PurgeLimiterTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Persistence\PurgeLimiter;
 
-class PurgeLimiterTest extends PHPUnit_Framework_TestCase
+class PurgeLimiterTest extends TestCase
 {
     private $_path;
 
diff --git a/tst/Persistence/ServerSaltTest.php b/tst/Persistence/ServerSaltTest.php
index ecdc0f83..34199d68 100644
--- a/tst/Persistence/ServerSaltTest.php
+++ b/tst/Persistence/ServerSaltTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Persistence\ServerSalt;
 
-class ServerSaltTest extends PHPUnit_Framework_TestCase
+class ServerSaltTest extends TestCase
 {
     private $_path;
 
diff --git a/tst/Persistence/TrafficLimiterTest.php b/tst/Persistence/TrafficLimiterTest.php
index 73769380..b2f5746a 100644
--- a/tst/Persistence/TrafficLimiterTest.php
+++ b/tst/Persistence/TrafficLimiterTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Persistence\TrafficLimiter;
 
-class TrafficLimiterTest extends PHPUnit_Framework_TestCase
+class TrafficLimiterTest extends TestCase
 {
     private $_path;
 
diff --git a/tst/RequestTest.php b/tst/RequestTest.php
index 9b440be0..f323d8f1 100644
--- a/tst/RequestTest.php
+++ b/tst/RequestTest.php
@@ -1,8 +1,9 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Request;
 
-class RequestTest extends PHPUnit_Framework_TestCase
+class RequestTest extends TestCase
 {
     public function setUp()
     {
diff --git a/tst/ViewTest.php b/tst/ViewTest.php
index 61530521..d46f63bd 100644
--- a/tst/ViewTest.php
+++ b/tst/ViewTest.php
@@ -1,9 +1,10 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\I18n;
 use PrivateBin\View;
 
-class ViewTest extends PHPUnit_Framework_TestCase
+class ViewTest extends TestCase
 {
     private static $error = 'foo bar';
 
diff --git a/tst/Vizhash16x16Test.php b/tst/Vizhash16x16Test.php
index afcda562..95a29681 100644
--- a/tst/Vizhash16x16Test.php
+++ b/tst/Vizhash16x16Test.php
@@ -1,9 +1,10 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use PrivateBin\Persistence\ServerSalt;
 use PrivateBin\Vizhash16x16;
 
-class Vizhash16x16Test extends PHPUnit_Framework_TestCase
+class Vizhash16x16Test extends TestCase
 {
     private $_file;