diff --git a/README.md b/README.md
index d99d06f..1ea645a 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,7 @@
 
 ## <a name="dependencies"></a> Dependencies
 
--   [v5.6 <= PHP <= v7.0.15](http://php.net/downloads.php)
+-   [PHP >= 8.1](http://php.net/downloads.php)
 
 ## <a name="installation"></a> Installation
 
diff --git a/composer.json b/composer.json
index 8dae19f..61d4b04 100644
--- a/composer.json
+++ b/composer.json
@@ -14,8 +14,8 @@
   "type": "library",
   "require": {
     "mustache/mustache": "^2.11.1",
-    "guzzlehttp/guzzle": "~6.0",
-    "php": ">=5.5",
+    "guzzlehttp/guzzle": "^7.0",
+    "php": ">=8.1",
     "psr/log": "^1.0.2"
   },
   "config": {
@@ -27,8 +27,8 @@
     }
   },
   "require-dev": {
-    "phpunit/phpunit": "5.6.*",
-    "mockery/mockery": "0.9.*",
+    "phpunit/phpunit": "^7.5",
+    "mockery/mockery": "^1.3",
     "overtrue/phplint": "^1.1"
   },
   "autoload-dev": {
diff --git a/src/CookieV3.php b/src/CookieV3.php
index 3d51a9f..49f8d16 100644
--- a/src/CookieV3.php
+++ b/src/CookieV3.php
@@ -19,7 +19,7 @@ public function __construct($pxCtx, $pxConfig)
 
         $payloadParts = explode(":", $pxCtx->getPxCookie());
         if (count($payloadParts) < $cookieValidPartsNumber) {
-            return null;
+            throw new PerimeterxException("Invalid cookie format: expected at least {$cookieValidPartsNumber} parts");
         }
         list($hash, $cookie) = explode(":", $pxCtx->getPxCookie(), 2);
         $this->pxPayload = $cookie;
diff --git a/src/PerimeterxContext.php b/src/PerimeterxContext.php
index 4dd5c91..0ff697b 100644
--- a/src/PerimeterxContext.php
+++ b/src/PerimeterxContext.php
@@ -54,8 +54,8 @@ public function __construct($pxConfig, $additionalFields = null)
         }
         $this->http_method = $_SERVER['REQUEST_METHOD'];
         $this->sensitive_route = $this->checkSensitiveRoutePrefix($pxConfig['sensitive_routes'], $this->uri);
-        $this->loginCredentials = array_key_exists('loginCredentials', $additionalFields) ? $additionalFields['loginCredentials'] : null;
-        $this->graphqlFields = array_key_exists('graphqlFields', $additionalFields) ? $additionalFields['graphqlFields'] : null;
+        $this->loginCredentials = (is_array($additionalFields) && array_key_exists('loginCredentials', $additionalFields)) ? $additionalFields['loginCredentials'] : null;
+        $this->graphqlFields = (is_array($additionalFields) && array_key_exists('graphqlFields', $additionalFields)) ? $additionalFields['graphqlFields'] : null;
         $this->requestId = PerimeterxUtils::createUuidV4();
     }
 
diff --git a/src/TokenV3.php b/src/TokenV3.php
index ad27898..be8974f 100644
--- a/src/TokenV3.php
+++ b/src/TokenV3.php
@@ -20,7 +20,7 @@ public function __construct($pxCtx, $pxConfig, $payload)
 
         $payloadParts = explode(":", $payload);
         if (count($payloadParts) < $cookieValidPartsNumber) {
-            return null;
+            throw new PerimeterxException("Invalid token format: expected at least {$cookieValidPartsNumber} parts");
         }
         list($hash, $token) = explode(":", $payload, 2);
 
diff --git a/tests/CredentialsIntelligence/Protocol/V2CredentialsIntelligenceProtocolTest.php b/tests/CredentialsIntelligence/Protocol/V2CredentialsIntelligenceProtocolTest.php
index 65a12f9..0cc828c 100644
--- a/tests/CredentialsIntelligence/Protocol/V2CredentialsIntelligenceProtocolTest.php
+++ b/tests/CredentialsIntelligence/Protocol/V2CredentialsIntelligenceProtocolTest.php
@@ -1,10 +1,11 @@
 <?php
+use PHPUnit\Framework\TestCase;
 
 use Perimeterx\CredentialsIntelligence\Protocol\V2CredentialsIntelligenceProtocol;
 use Perimeterx\CredentialsIntelligence\LoginCredentialsFields;
 use Perimeterx\CredentialsIntelligence\Protocol\CIVersion;
 
-class V2CredentialsIntelligenceProtocolTests extends PHPUnit_Framework_TestCase {
+class V2CredentialsIntelligenceProtocolTests extends PHPUnit\Framework\TestCase {
 
     /**
      * @dataProvider provideCredentialsAndExpectedHashes
diff --git a/tests/PerimeterxConfigurationValidatorTest.php b/tests/PerimeterxConfigurationValidatorTest.php
index a475d26..77bd3d9 100644
--- a/tests/PerimeterxConfigurationValidatorTest.php
+++ b/tests/PerimeterxConfigurationValidatorTest.php
@@ -3,13 +3,13 @@
 use PHPUnit\Framework\TestCase;
 use Perimeterx\Perimeterx;
 
-class PerimeterxConfigurationValidatorTest extends PHPUnit_Framework_TestCase
+class PerimeterxConfigurationValidatorTest extends TestCase
 {
 
     protected $params;
     protected $px;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $this->params = [
             'app_id' => 'PX_APP_ID',
@@ -20,7 +20,7 @@ protected function setUp()
         ];
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         $reflection = new ReflectionClass($this->px);
         $instance = $reflection->getProperty('instance');
diff --git a/tests/PerimeterxCookieV3ValidatorTest.php b/tests/PerimeterxCookieV3ValidatorTest.php
index de029dd..7f2fdb5 100644
--- a/tests/PerimeterxCookieV3ValidatorTest.php
+++ b/tests/PerimeterxCookieV3ValidatorTest.php
@@ -6,7 +6,7 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Log\AbstractLogger;
 
-class PerimeterxCookieV3ValidatorTest extends PHPUnit_Framework_TestCase
+class PerimeterxCookieV3ValidatorTest extends PHPUnit\Framework\TestCase
 {
 
     // randomly generated fake values
diff --git a/tests/PerimeterxCookieValidatorTest.php b/tests/PerimeterxCookieValidatorTest.php
index 8e8c9b5..8e5cb34 100644
--- a/tests/PerimeterxCookieValidatorTest.php
+++ b/tests/PerimeterxCookieValidatorTest.php
@@ -6,7 +6,7 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Log\AbstractLogger;
 
-class PerimeterxCookieValidatorTest extends PHPUnit_Framework_TestCase
+class PerimeterxCookieValidatorTest extends PHPUnit\Framework\TestCase
 {
 
     // randomly generated fake values
diff --git a/tests/PerimeterxDataEnrichmentTest.php b/tests/PerimeterxDataEnrichmentTest.php
index 9f23491..ae8360d 100644
--- a/tests/PerimeterxDataEnrichmentTest.php
+++ b/tests/PerimeterxDataEnrichmentTest.php
@@ -8,7 +8,7 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Log\AbstractLogger;
 
-class PerimeterxDataEnrichmentTest extends PHPUnit_Framework_TestCase {
+class PerimeterxDataEnrichmentTest extends PHPUnit\Framework\TestCase {
     const COOKIE_KEY = '549Z5UsasvfmVS6kAR3r4ydPnQdnnW4Gcwk35hj5tatZ5B2dqjrQvMMyLAJN5de3';
 
     public function testNoPxdeCookie() {
diff --git a/tests/PerimeterxFieldExtractorManagerTest.php b/tests/PerimeterxFieldExtractorManagerTest.php
index 2011d8a..79d630a 100644
--- a/tests/PerimeterxFieldExtractorManagerTest.php
+++ b/tests/PerimeterxFieldExtractorManagerTest.php
@@ -4,8 +4,9 @@
 use Perimeterx\CredentialsIntelligence\PerimeterxFieldExtractor;
 use Perimeterx\CredentialsIntelligence\PerimeterxFieldExtractorManager;
 use Perimeterx\CredentialsIntelligence\Protocol\V1CredentialsIntelligenceProtocol;
+use PHPUnit\Framework\TestCase;
 
-class PerimeterxFieldExtractorManagerTest extends PHPUnit_Framework_TestCase
+class PerimeterxFieldExtractorManagerTest extends TestCase
 {
     const LOGIN_REQUEST_URI = "/login";
     const LOGIN_REQUEST_METHOD = "POST";
@@ -32,7 +33,7 @@ class PerimeterxFieldExtractorManagerTest extends PHPUnit_Framework_TestCase
      */
     private $fieldExtractorManager;
 
-    public function setUp() {
+    protected function setUp(): void {
         $mapKey = PerimeterxFieldExtractorManager::generateMapKey(self::LOGIN_REQUEST_URI, self::LOGIN_REQUEST_METHOD);
         $mockExtractor = $this->createMock(PerimeterxFieldExtractor::class);
         $mockExtractor
diff --git a/tests/PerimeterxFirstPartyClientTest.php b/tests/PerimeterxFirstPartyClientTest.php
index 07f9d7b..8ab034c 100644
--- a/tests/PerimeterxFirstPartyClientTest.php
+++ b/tests/PerimeterxFirstPartyClientTest.php
@@ -1,4 +1,5 @@
 <?php
+use PHPUnit\Framework\TestCase;
 
 use GuzzleHttp\Psr7\Response;
 use Perimeterx\PerimeterxFirstPartyClient;
@@ -7,7 +8,7 @@
 use PerimeterxTests\MockHttpClient;
 use PerimeterxTests\TestUtils;
 
-class PerimeterxFirstPartyClientTest extends PHPUnit_Framework_TestCase {
+class PerimeterxFirstPartyClientTest extends PHPUnit\Framework\TestCase {
     private function getTestPxConfig() {
         $pxConfig = [
             'app_id' => 'PX_APP_ID',
diff --git a/tests/PerimeterxOriginalTokenValidatorTest.php b/tests/PerimeterxOriginalTokenValidatorTest.php
index b0c814a..a7ca257 100644
--- a/tests/PerimeterxOriginalTokenValidatorTest.php
+++ b/tests/PerimeterxOriginalTokenValidatorTest.php
@@ -6,7 +6,7 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Log\AbstractLogger;
 
-class PerimeterxOriginalTokenValidatorTest extends PHPUnit_Framework_TestCase
+class PerimeterxOriginalTokenValidatorTest extends PHPUnit\Framework\TestCase
 {
     // randomly generated fake values
     const COOKIE_KEY = '549Z5UsasvfmVS6kAR3r4ydPnQdnnW4Gcwk35hj5tatZ5B2dqjrQvMMyLAJN5de3';
diff --git a/tests/PerimeterxS2SValidatorTest.php b/tests/PerimeterxS2SValidatorTest.php
index dbd6f34..bf2f8e9 100644
--- a/tests/PerimeterxS2SValidatorTest.php
+++ b/tests/PerimeterxS2SValidatorTest.php
@@ -1,4 +1,5 @@
 <?php
+use PHPUnit\Framework\TestCase;
 
 use Perimeterx\Perimeterx;
 use Perimeterx\PerimeterxContext;
@@ -6,7 +7,7 @@
 use Perimeterx\PerimeterxHttpClient;
 use Psr\Log\AbstractLogger;
 
-class PerimeterxS2SValidatorTest extends PHPUnit_Framework_TestCase
+class PerimeterxS2SValidatorTest extends PHPUnit\Framework\TestCase
 {
     // randomly generated fake values
     const COOKIE_KEY = '549Z5UsasvfmVS6kAR3r4ydPnQdnnW4Gcwk35hj5tatZ5B2dqjrQvMMyLAJN5de3';
diff --git a/tests/PerimeterxUtilsTest.php b/tests/PerimeterxUtilsTest.php
index 585924c..88753fb 100644
--- a/tests/PerimeterxUtilsTest.php
+++ b/tests/PerimeterxUtilsTest.php
@@ -2,6 +2,7 @@
 
 use Perimeterx\PerimeterxUtils;
 use PerimeterxTests\TestUtils;
+use PHPUnit\Framework\TestCase;
 
 class PerimeterxUtilsDouble extends PerimeterxUtils {
     public static function setInputStreamName($inputStreamName) {
@@ -9,14 +10,14 @@ public static function setInputStreamName($inputStreamName) {
     }
 }
 
-class PerimeterxUtilsTest extends PHPUnit_Framework_TestCase {
+class PerimeterxUtilsTest extends TestCase {
     const TEMP_STREAM_NAME = "file://" . __DIR__ . "/tmp.txt";
 
-    public function setUp() {
+    protected function setUp(): void {
         PerimeterxUtilsDouble::setInputStreamName(self::TEMP_STREAM_NAME);
     }
 
-    public function tearDown() {
+    protected function tearDown(): void {
         if (file_exists(self::TEMP_STREAM_NAME)) {
             unlink(self::TEMP_STREAM_NAME);
         }