diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 594feffa..6207da1e 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -45,8 +45,8 @@ jobs:
         - name: PHPStan code analysis
           run: php vendor/bin/phpstan analyze
 
-        - name: PHPinsights code analysis
-          run: php vendor/bin/phpinsights analyse --no-interaction
+#        - name: PHPinsights code analysis
+#          run: php vendor/bin/phpinsights analyse --no-interaction
 
 #        - name: Execute Rector
 #          continue-on-error: true
diff --git a/composer.json b/composer.json
index 5cf7f5de..d85066e0 100644
--- a/composer.json
+++ b/composer.json
@@ -27,12 +27,10 @@
         "ext-gd" : "*",
         "ext-exif" : "*",
         "squizlabs/php_codesniffer" : ">=3.7",
-        "phpunit/phpunit" : "^10 || ^11 || ^12",
+        "phpunit/phpunit" : "^10 || ^11 || ^12 || ^13",
         "phpstan/extension-installer": "^1.4",
         "phpstan/phpstan": "^2",
-        "phpstan/phpstan-phpunit": "^2",
-        "rector/rector": "^2",
-        "nunomaduro/phpinsights": "^2"
+        "phpstan/phpstan-phpunit": "^2"
     },
     "config": {
         "allow-plugins": {
diff --git a/src/PelConvert.php b/src/PelConvert.php
index 79cb2428..11ef10ea 100644
--- a/src/PelConvert.php
+++ b/src/PelConvert.php
@@ -106,9 +106,15 @@ public static function longToBytes(int $value, bool $endian): string
          */
         $hex = str_pad(base_convert((string) $value, 10, 16), 8, '0', STR_PAD_LEFT);
         if ($endian === self::LITTLE_ENDIAN) {
-            return chr((int) hexdec($hex[6] . $hex[7])) . chr((int) hexdec($hex[4] . $hex[5])) . chr((int) hexdec($hex[2] . $hex[3])) . chr((int) hexdec($hex[0] . $hex[1]));
+            return chr(((int) hexdec($hex[6] . $hex[7])) & 0xFF) .
+              chr(((int) hexdec($hex[4] . $hex[5])) & 0xFF) .
+              chr(((int) hexdec($hex[2] . $hex[3])) & 0xFF) .
+              chr(((int) hexdec($hex[0] . $hex[1])) & 0xFF);
         }
-        return chr((int) hexdec($hex[0] . $hex[1])) . chr((int) hexdec($hex[2] . $hex[3])) . chr((int) hexdec($hex[4] . $hex[5])) . chr((int) hexdec($hex[6] . $hex[7]));
+        return chr(((int) hexdec($hex[0] . $hex[1])) & 0xFF) .
+          chr(((int) hexdec($hex[2] . $hex[3])) & 0xFF) .
+          chr(((int) hexdec($hex[4] . $hex[5])) & 0xFF) .
+          chr(((int) hexdec($hex[6] . $hex[7])) & 0xFF);
     }
 
     /**
diff --git a/src/PelEntryByte.php b/src/PelEntryByte.php
index a7ec96b3..b851983a 100644
--- a/src/PelEntryByte.php
+++ b/src/PelEntryByte.php
@@ -44,6 +44,6 @@ public function __construct(int $tag, int ...$value)
      */
     public function numberToBytes(int $number, bool $order): string
     {
-        return chr($number);
+        return chr($number & 0xFF);
     }
 }
diff --git a/src/PelJpegMarker.php b/src/PelJpegMarker.php
index 28d8e4ab..58168ae8 100644
--- a/src/PelJpegMarker.php
+++ b/src/PelJpegMarker.php
@@ -461,7 +461,7 @@ public static function isValid(int $marker): bool
      */
     public static function getBytes(int $marker): string
     {
-        return chr($marker);
+        return chr($marker & 0xFF);
     }
 
     /**