diff --git a/composer.json b/composer.json
index 62ccdd3..a5e5989 100644
--- a/composer.json
+++ b/composer.json
@@ -46,13 +46,13 @@
         "php" : "^8.1"
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "^3.53.0",
-        "phpstan/phpstan": "^1.10.66",
-        "phpstan/phpstan-deprecation-rules": "^1.1.4",
-        "phpstan/phpstan-phpunit": "^1.3.16",
-        "phpstan/phpstan-strict-rules": "^1.5.3",
-        "phpunit/phpunit": "^10.5.15 || ^11.1.1",
-        "symfony/var-dumper": "^6.4.6"
+        "friendsofphp/php-cs-fixer": "^3.64.0",
+        "phpstan/phpstan": "^1.12.3",
+        "phpstan/phpstan-deprecation-rules": "^1.2.1",
+        "phpstan/phpstan-phpunit": "^1.4.0",
+        "phpstan/phpstan-strict-rules": "^1.6.0",
+        "phpunit/phpunit": "^10.5.15 || ^11.3.4",
+        "symfony/var-dumper": "^6.4.11"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Duration.php b/src/Duration.php
index 743b9c0..a8015cb 100644
--- a/src/Duration.php
+++ b/src/Duration.php
@@ -137,7 +137,7 @@ public static function fromChronoString(string $duration): self
             'minute' => $matches['minute'],
             'second' => $matches['second'],
             'fraction' => $matches['fraction'] ?? null,
-            'sign' => $matches['sign'] ?? null,
+            'sign' => $matches['sign'],
         ]);
     }
 
@@ -153,11 +153,11 @@ public static function fromTimeString(string $duration): self
         }
 
         return self::fromUnits([
-            'hour' => $matches['hour'] ?? null,
-            'minute' => $matches['minute'] ?? null,
+            'hour' => $matches['hour'],
+            'minute' => $matches['minute'],
             'second' => $matches['second'] ?? '0',
             'fraction' => $matches['fraction'] ?? null,
-            'sign' => $matches['sign'] ?? null,
+            'sign' => $matches['sign'],
         ]);
     }