diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6b00e3b..37f6ab6 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,15 +17,12 @@ jobs:
     strategy:
       matrix:
         php-versions: 
-          - '5.5'
-          - '5.6'
-          - '7.0'
           - '7.1'
           - '7.2'
-          # - '8.0'
-          # - '8.1'
-          # - '8.2'
-          # - '8.3'
+          - '8.0'
+          - '8.1'
+          - '8.2'
+          - '8.3'
 
     steps:
       - uses: actions/checkout@v4
diff --git a/composer.json b/composer.json
index e12096c..0666f28 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
         }
     ],
     "require-dev": {
-        "phpunit/phpunit": "~4.0"
+        "phpunit/phpunit": "^5.0|^6.0|^7.0|^8.0|^9.0|^10.5|^11.0"
     },
     "require": {
         "ext-pcntl": "*",
diff --git a/tests/RedisSimpleLockFactoryTest.php b/tests/RedisSimpleLockFactoryTest.php
index db6beb0..45bd09f 100644
--- a/tests/RedisSimpleLockFactoryTest.php
+++ b/tests/RedisSimpleLockFactoryTest.php
@@ -1,13 +1,14 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use TH\RedisLock\RedisSimpleLock;
 use TH\RedisLock\RedisSimpleLockFactory;
 
-class RedisSimpleLockFactoryTest extends PHPUnit_Framework_TestCase
+class RedisSimpleLockFactoryTest extends TestCase
 {
     private $redisClient;
 
-    protected function setUp()
+    public function setUp(): void
     {
         $this->redisClient = new \Predis\Client(getenv('REDIS_URI'));
         $this->redisClient->flushdb();
diff --git a/tests/RedisSimpleLockTest.php b/tests/RedisSimpleLockTest.php
index 64c2396..5d4cff5 100644
--- a/tests/RedisSimpleLockTest.php
+++ b/tests/RedisSimpleLockTest.php
@@ -1,12 +1,13 @@
 <?php
 
+use PHPUnit\Framework\TestCase;
 use TH\RedisLock\RedisSimpleLock;
 
-class RedisSimpleLockTest extends PHPUnit_Framework_TestCase
+class RedisSimpleLockTest extends TestCase
 {
     private $redisClient;
 
-    protected function setUp()
+    public function setUp(): void
     {
         $this->redisClient = new \Predis\Client(getenv("REDIS_URI"));
         $this->redisClient->flushdb();
@@ -20,7 +21,7 @@ public function testLock()
         $lock1->acquire();
 
         // Only the second acquire is supposed to fail
-        $this->setExpectedException("Exception");
+        $this->expectException("Exception");
         $lock2->acquire();
     }