diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 57967cf..b521e6d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,6 +11,17 @@ jobs:
     strategy:
       matrix:
         php:
+          - 8.3
+          - 8.2
+          - 8.1
+          - 8.0
+          - 7.4
+          - 7.3
+          - 7.2
+          - 7.1
+          - 7.0
+          - 5.6
+          - 5.5
           - 5.4
           - 5.3
     steps:
@@ -21,3 +32,6 @@ jobs:
           coverage: xdebug
       - run: composer install
       - run: vendor/bin/phpunit --coverage-text
+        if: ${{ matrix.php >= 7.3 }}
+      - run: vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy
+        if: ${{ matrix.php < 7.3 }}
diff --git a/composer.json b/composer.json
index 66c804a..a6464b0 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "php": ">=5.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.36"
+        "phpunit/phpunit": "^9.6 || ^5.7 || ^4.8.36"
     },
     "autoload": {
         "psr-0": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index f66a042..bb9f22c 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,20 +1,22 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- PHPUnit configuration file with old format for legacy PHPUnit -->
+<!-- PHPUnit configuration file with new format for PHPUnit 9.6+ -->
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.6/phpunit.xsd"
          bootstrap="vendor/autoload.php"
-         colors="true">
+         cacheResult="false"
+         colors="true"
+         convertDeprecationsToExceptions="true">
     <testsuites>
         <testsuite name="Redis Protocol Test Suite">
             <directory>./tests/</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
+    <coverage>
+        <include>
             <directory>./src/</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
     <php>
         <ini name="error_reporting" value="-1" />
     </php>
diff --git a/phpunit.xml.legacy b/phpunit.xml.legacy
new file mode 100644
index 0000000..f66a042
--- /dev/null
+++ b/phpunit.xml.legacy
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with old format for legacy PHPUnit -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true">
+    <testsuites>
+        <testsuite name="Redis Protocol Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+</phpunit>
diff --git a/tests/FactoryTest.php b/tests/FactoryTest.php
index b669223..a645127 100644
--- a/tests/FactoryTest.php
+++ b/tests/FactoryTest.php
@@ -6,7 +6,10 @@ class FactoryTest extends TestCase
 {
     private $factory;
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpFactory()
     {
         $this->factory = new Factory();
     }
diff --git a/tests/Model/AbstractModelTest.php b/tests/Model/AbstractModelTest.php
index 1358533..7324850 100644
--- a/tests/Model/AbstractModelTest.php
+++ b/tests/Model/AbstractModelTest.php
@@ -8,7 +8,10 @@ abstract class AbstractModelTest extends TestCase
 
     abstract protected function createModel($value);
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpSerializer()
     {
         $this->serializer = new RecursiveSerializer();
     }
diff --git a/tests/Model/ErrorReplyTest.php b/tests/Model/ErrorReplyTest.php
index 2585b08..16497fb 100644
--- a/tests/Model/ErrorReplyTest.php
+++ b/tests/Model/ErrorReplyTest.php
@@ -6,7 +6,7 @@ class ErrorReplyTest extends AbstractModelTest
 {
     protected function createModel($value)
     {
-        return new ErrorReply($value);
+        return new ErrorReply((string) $value);
     }
 
     public function testError()
diff --git a/tests/Model/MultiBulkReplyTest.php b/tests/Model/MultiBulkReplyTest.php
index 04dd389..ff4a0c3 100644
--- a/tests/Model/MultiBulkReplyTest.php
+++ b/tests/Model/MultiBulkReplyTest.php
@@ -36,10 +36,10 @@ public function testNullMultiBulkReply()
     /**
      * @param MultiBulkReply $model
      * @depends testNullMultiBulkReply
-     * @expectedException UnexpectedValueException
      */
     public function testNullMultiBulkReplyIsNotARequest(MultiBulkReply $model)
     {
+        $this->setExpectedException('UnexpectedValueException');
         $model->getRequestModel();
     }
 
@@ -91,10 +91,10 @@ public function testMixedReply()
     /**
      * @param MultiBulkReply $model
      * @depends testMixedReply
-     * @expectedException UnexpectedValueException
      */
     public function testMixedReplyIsNotARequest(MultiBulkReply $model)
     {
+        $this->setExpectedException('UnexpectedValueException');
         $model->getRequestModel();
     }
 
diff --git a/tests/Parser/AbstractParserTest.php b/tests/Parser/AbstractParserTest.php
index 3d45c20..24c737c 100644
--- a/tests/Parser/AbstractParserTest.php
+++ b/tests/Parser/AbstractParserTest.php
@@ -13,7 +13,10 @@ abstract class AbstractParserTest extends TestCase
 
     abstract protected function createParser();
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpParser()
     {
         $this->parser = $this->createParser();
         $this->assertInstanceOf('Clue\Redis\Protocol\Parser\ParserInterface', $this->parser);
diff --git a/tests/Parser/RequestParserTest.php b/tests/Parser/RequestParserTest.php
index 645b673..bc95256 100644
--- a/tests/Parser/RequestParserTest.php
+++ b/tests/Parser/RequestParserTest.php
@@ -110,23 +110,19 @@ public function testWhitespaceInlineIsIgnored()
         $this->assertEquals(array(), $this->parser->pushIncoming($message));
     }
 
-    /**
-     * @expectedException Clue\Redis\Protocol\Parser\ParserException
-     */
     public function testInvalidMultiBulkMustContainBulk()
     {
         $message = "*1\r\n:123\r\n";
 
+        $this->setExpectedException('Clue\Redis\Protocol\Parser\ParserException');
         $this->parser->pushIncoming($message);
     }
 
-    /**
-     * @expectedException Clue\Redis\Protocol\Parser\ParserException
-     */
     public function testInvalidBulkLength()
     {
         $message = "*1\r\n$-1\r\n";
 
+        $this->setExpectedException('Clue\Redis\Protocol\Parser\ParserException');
         $this->parser->pushIncoming($message);
     }
 }
diff --git a/tests/Parser/ResponseParserTest.php b/tests/Parser/ResponseParserTest.php
index d102621..17ed387 100644
--- a/tests/Parser/ResponseParserTest.php
+++ b/tests/Parser/ResponseParserTest.php
@@ -120,11 +120,9 @@ public function testParsingMultiBulkReplyWithNullElement()
         $this->assertEquals(array('foo', null, 'bar'), $data);
     }
 
-    /**
-     * @expectedException Clue\Redis\Protocol\Parser\ParserException
-     */
     public function testParseError()
     {
+        $this->setExpectedException('Clue\Redis\Protocol\Parser\ParserException');
         $this->parser->pushIncoming("invalid string\r\n");
     }
 }
diff --git a/tests/Serializer/AbstractSerializerTest.php b/tests/Serializer/AbstractSerializerTest.php
index a6d1c40..e3dc625 100644
--- a/tests/Serializer/AbstractSerializerTest.php
+++ b/tests/Serializer/AbstractSerializerTest.php
@@ -1,16 +1,21 @@
 <?php
 
 use Clue\Redis\Protocol\Serializer\SerializerInterface;
-//use Exception;
 
 abstract class AbstractSerializerTest extends TestCase
 {
+    /** @var SerializerInterface */
+    private $serializer;
+
     /**
      * @return SerializerInterface
      */
     abstract protected function createSerializer();
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpSerializer()
     {
         $this->serializer = $this->createSerializer();
     }
@@ -89,19 +94,15 @@ public function testErrorReply()
         $this->assertEquals($model->getMessageSerialized($this->serializer), $this->serializer->getReplyMessage(new Exception('ERR failure')));
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testInvalidArgument()
     {
+        $this->setExpectedException('InvalidArgumentException');
         $this->serializer->createReplyModel((object)array());
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testInvalidReplyData()
     {
+        $this->setExpectedException('InvalidArgumentException');
         $this->serializer->getReplyMessage((object)array());
     }
 
diff --git a/tests/TestCase.php b/tests/TestCase.php
index ac3b704..3f65834 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -1,5 +1,21 @@
 <?php
 
-class TestCase extends PHPUnit_Framework_TestCase
+class TestCase extends \PHPUnit\Framework\TestCase
 {
+    public function setExpectedException($exception, $exceptionMessage = '', $exceptionCode = null)
+    {
+        if (method_exists($this, 'expectException')) {
+            // PHPUnit 5.2+
+            $this->expectException($exception);
+            if ($exceptionMessage !== '') {
+                $this->expectExceptionMessage($exceptionMessage);
+            }
+            if ($exceptionCode !== null) {
+                $this->expectExceptionCode($exceptionCode);
+            }
+        } else {
+            // legacy PHPUnit
+            parent::setExpectedException($exception, $exceptionMessage, $exceptionCode);
+        }
+    }
 }