diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 6f165ad..15605d5 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -1,6 +1,6 @@
 {
 	"name": "PHP",
-	"image": "mcr.microsoft.com/devcontainers/php:8.1-bullseye",
+	"image": "mcr.microsoft.com/devcontainers/php:8.2-bullseye",
 
 	// Features to add to the dev container. More info: https://containers.dev/features.
 	// "features": {},
diff --git a/composer.json b/composer.json
index b5b82b7..fd45b24 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
     "require-dev": {
         "phpunit/phpunit": "^9.6 || ^10.0 || ^11.0",
         "consolidation/robo": "^4.0 || ^5.0",
-        "phpstan/phpstan": "^1.3.0",
+        "phpstan/phpstan": "^2.0.1",
         "phlak/semver": "^5.0 || ^6.0"
     },
     "suggest": {
diff --git a/composer.lock b/composer.lock
index 175854e..28c907c 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": "3126ba14863152346bcfbfb9ec84db8b",
+    "content-hash": "e7b31e0ef18faeafa1ce16fb9bb420c2",
     "packages": [],
     "packages-dev": [
         {
@@ -964,20 +964,20 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "1.12.0",
+            "version": "2.0.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "384af967d35b2162f69526c7276acadce534d0e1"
+                "reference": "ab4e9b4415a5fc9e4d27f7fe16c8bc9d067dcd6d"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/384af967d35b2162f69526c7276acadce534d0e1",
-                "reference": "384af967d35b2162f69526c7276acadce534d0e1",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/ab4e9b4415a5fc9e4d27f7fe16c8bc9d067dcd6d",
+                "reference": "ab4e9b4415a5fc9e4d27f7fe16c8bc9d067dcd6d",
                 "shasum": ""
             },
             "require": {
-                "php": "^7.2|^8.0"
+                "php": "^7.4|^8.0"
             },
             "conflict": {
                 "phpstan/phpstan-shim": "*"
@@ -1018,7 +1018,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2024-08-27T09:18:05+00:00"
+            "time": "2024-11-11T15:43:04+00:00"
         },
         {
             "name": "phpunit/php-code-coverage",
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 3ff6fa8..1edd4ad 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,4 +1,5 @@
 parameters:
   level: 7
   paths:
-    - src
\ No newline at end of file
+    - src
+  treatPhpDocTypesAsCertain: false
\ No newline at end of file
diff --git a/src/SimpleJWT/Crypt/Encryption/AESGCM.php b/src/SimpleJWT/Crypt/Encryption/AESGCM.php
index 5fd0aa0..42a1c2f 100644
--- a/src/SimpleJWT/Crypt/Encryption/AESGCM.php
+++ b/src/SimpleJWT/Crypt/Encryption/AESGCM.php
@@ -63,8 +63,6 @@ public function __construct(?string $alg) {
      * {@inheritdoc}
      */
     public function getSupportedAlgs(): array {
-        if (!version_compare(PHP_VERSION, '7.1', '>=')) return [];
-
         $ciphers = array_map('strtolower', openssl_get_cipher_methods());
         $results = [];
 
diff --git a/src/SimpleJWT/Crypt/KeyManagement/PBES2.php b/src/SimpleJWT/Crypt/KeyManagement/PBES2.php
index a08ad83..93426b3 100644
--- a/src/SimpleJWT/Crypt/KeyManagement/PBES2.php
+++ b/src/SimpleJWT/Crypt/KeyManagement/PBES2.php
@@ -57,7 +57,7 @@ class PBES2 extends BaseAlgorithm implements KeyEncryptionAlgorithm {
         'PBES2-HS512+A256KW' => ['hash' => 'sha512']
     ];
 
-    /** @var string $hash_alg */
+    /** @var truthy-string $hash_alg */
     protected $hash_alg;
 
     /** @var int $iterations */
@@ -162,8 +162,10 @@ protected function generateSaltInput(): string {
      */
     private function generateKeyFromPassword(string $password, array $headers): string {
         $salt = $headers['alg'] . "\x00" . Util::base64url_decode($headers['p2s']);
+        /** @var int<0, max> $length */
+        $length = intdiv($this->getAESKWKeySize(), 8);
 
-        return hash_pbkdf2($this->hash_alg, $password, $salt, $headers['p2c'], $this->getAESKWKeySize() / 8, true);
+        return hash_pbkdf2($this->hash_alg, $password, $salt, $headers['p2c'], $length, true);
     }
 }
 ?>
diff --git a/src/SimpleJWT/Util/ASN1/Value.php b/src/SimpleJWT/Util/ASN1/Value.php
index a99c937..fcaaa48 100644
--- a/src/SimpleJWT/Util/ASN1/Value.php
+++ b/src/SimpleJWT/Util/ASN1/Value.php
@@ -35,6 +35,7 @@
 
 namespace SimpleJWT\Util\ASN1;
 
+use \SimpleJWT\Util\Util;
 use \InvalidArgumentException;
 
 /**
@@ -207,7 +208,7 @@ static public function oid(string $value): self {
      * @return Value
      */
     static public function sequence(array $value): self {
-        if (!is_array($value)) {
+        if (!Util::array_is_list($value)) {
             throw new InvalidArgumentException('Not a sequence');
         }
         return new self(static::SEQUENCE, $value);
diff --git a/src/SimpleJWT/Util/BigNum.php b/src/SimpleJWT/Util/BigNum.php
index 3ca37a9..02106f2 100644
--- a/src/SimpleJWT/Util/BigNum.php
+++ b/src/SimpleJWT/Util/BigNum.php
@@ -68,7 +68,7 @@ public function __construct($str = 0, int $base = 10) {
                 $this->value = $value;
                 return;
             default:
-                if (!is_integer($base) || ($base < 2) || ($base > 36))
+                if (($base < 2) || ($base > 36))
                     throw new \InvalidArgumentException('$base cannot be less than 2 or greater than 36');
 
                 $value = (new BigNum(0))->value;
diff --git a/src/SimpleJWT/Util/CBOR/CBOR.php b/src/SimpleJWT/Util/CBOR/CBOR.php
index 510c7a1..e89ff3f 100644
--- a/src/SimpleJWT/Util/CBOR/CBOR.php
+++ b/src/SimpleJWT/Util/CBOR/CBOR.php
@@ -233,7 +233,7 @@ protected function decodeNext(string $data, int &$pos): ?DataItem {
                     }
                     break;
                 default:
-                    assert(true);
+                    throw new CBORException('Invalid major type: expected list or map, got ' . ($major_type >> 5));;
             }
         }
 
diff --git a/src/SimpleJWT/Util/CBOR/DataItem.php b/src/SimpleJWT/Util/CBOR/DataItem.php
index 3aa8de3..6e0db05 100644
--- a/src/SimpleJWT/Util/CBOR/DataItem.php
+++ b/src/SimpleJWT/Util/CBOR/DataItem.php
@@ -123,7 +123,6 @@ class DataItem {
      * @param int $type the type
      * @param mixed $value the native PHP value
      * @param int $tag the tag number (i.e. excluding the class and constructed bit masks)
-     * @throws InvalidArgumentException
      */
     function __construct(int $type, $value, int $tag = null) {
         $this->type = $type;
@@ -233,7 +232,7 @@ static public function simple(int $value): self {
      * @return DataItem
      */
     static public function list(array $value): self {
-        if (!is_array($value) || !self::array_is_list($value)) {
+        if (!Util::array_is_list($value)) {
             throw new InvalidArgumentException('Not an array');
         }
         return new self(static::LIST_TYPE, $value);
@@ -246,7 +245,7 @@ static public function list(array $value): self {
      * @return DataItem
      */
     static public function map(array $value): self {
-        if (!is_array($value)|| self::array_is_list($value)) {
+        if (Util::array_is_list($value)) {
             throw new InvalidArgumentException('Not an associative array');
         }
         return new self(static::MAP_TYPE, $value);
@@ -260,7 +259,7 @@ static public function default($value): self {
         if ($value instanceof DataItem) {
             return $value;
         } elseif (is_array($value)) {
-            if (self::array_is_list($value)) {
+            if (Util::array_is_list($value)) {
                 return static::list($value);
             } else {
                 return static::map($value);
@@ -424,19 +423,6 @@ protected function prettyPrint(int $indent = 0): string {
     public function __toString(): string {
         return $this->prettyPrint();
     }
-
-    /**
-     * Returns whether an array is a list.
-     * 
-     * This is a polyfill for PHP 8.1's array_as_list function.
-     * 
-     * @param array<mixed> $array
-     * @return bool if the array is a list
-     */
-    public static function array_is_list(array $array): bool {
-        if (function_exists('array_is_list')) return \array_is_list($array);
-        return $array === [] || (array_keys($array) === range(0, count($array) - 1));
-    }
 }
 
 ?>
diff --git a/src/SimpleJWT/Util/Util.php b/src/SimpleJWT/Util/Util.php
index f7fd756..4f45379 100644
--- a/src/SimpleJWT/Util/Util.php
+++ b/src/SimpleJWT/Util/Util.php
@@ -120,11 +120,7 @@ static public function secure_compare(string $str1, string $str2): bool {
      */
     static function packInt64(int $x): string {
         if (PHP_INT_SIZE == 8) {
-            if (version_compare(PHP_VERSION, '5.6.3', '>=')) {
-                return pack('J', $x);
-            } else {
-                return pack('NN', ($x & 0xFFFFFFFF00000000) >> 32, $x & ($x & 0x00000000FFFFFFFF)); 
-            }
+            return pack('J', $x);
         } else {
             // 32-bit system
             return "\x00\x00\x00\x00" . pack('N', $x);
@@ -143,6 +139,19 @@ static function packInt64(int $x): string {
     static function random_bytes(int $num_bytes): string {
         return random_bytes($num_bytes);
     }
+
+    /**
+     * Returns whether an array is a list.
+     * 
+     * This is a polyfill for PHP 8.1's array_as_list function.
+     * 
+     * @param array<mixed> $array
+     * @return bool if the array is a list
+     */
+    public static function array_is_list(array $array): bool {
+        if (function_exists('array_is_list')) return \array_is_list($array);
+        return $array === [] || (array_keys($array) === range(0, count($array) - 1));
+    }
 }
 
 ?>