diff --git a/build/phprectorconfig.php b/build/phprectorconfig.php
index 6cfd629..a2bb3f5 100644
--- a/build/phprectorconfig.php
+++ b/build/phprectorconfig.php
@@ -31,12 +31,12 @@
         codeQuality: true,
         codingStyle: true,
         strictBooleans: true,
+        instanceOf: true,
+        earlyReturn: true,
         //
         carbon: false,
         deadCode: false,
         doctrineCodeQuality: false,
-        earlyReturn: false,
-        instanceOf: false,
         naming: false,
         phpunitCodeQuality: false,
         privatization: false,
diff --git a/make/genchangelog.php b/make/genchangelog.php
index 9d820c8..1686ada 100644
--- a/make/genchangelog.php
+++ b/make/genchangelog.php
@@ -34,7 +34,7 @@ function stristartswith(string $haystack, string $needle): bool
 function correctAuthor(string $author): string
 {
     if ($author === "horstoeko" || $author === "ruff" || $author === "Daniel Erling") {
-        $author = "HorstOeko";
+        return "HorstOeko";
     }
 
     return $author;
diff --git a/make/genmethoddocs.php b/make/genmethoddocs.php
index 9c083b0..9463840 100644
--- a/make/genmethoddocs.php
+++ b/make/genmethoddocs.php
@@ -679,7 +679,7 @@ private function fixPhpType(string $string): string
         }
 
         if ($string === '$this') {
-            $string = 'static';
+            return 'static';
         }
 
         return $string;
diff --git a/src/ZugferdObjectHelper.php b/src/ZugferdObjectHelper.php
index db99112..a05d341 100644
--- a/src/ZugferdObjectHelper.php
+++ b/src/ZugferdObjectHelper.php
@@ -1447,19 +1447,29 @@ public function toDateTime(?string $dateTimeString, ?string $format): ?DateTime
 
         if ($format == "102") {
             return DateTime::createFromFormat("Ymd", $dateTimeString);
-        } elseif ($format == "101") {
+        }
+
+        if ($format == "101") {
             return DateTime::createFromFormat("ymd", $dateTimeString);
-        } elseif ($format == "201") {
+        }
+
+        if ($format == "201") {
             return DateTime::createFromFormat("ymdHi", $dateTimeString);
-        } elseif ($format == "202") {
+        }
+
+        if ($format == "202") {
             return DateTime::createFromFormat("ymdHis", $dateTimeString);
-        } elseif ($format == "203") {
+        }
+
+        if ($format == "203") {
             return DateTime::createFromFormat("YmdHi", $dateTimeString);
-        } elseif ($format == "204") {
+        }
+
+        if ($format == "204") {
             return DateTime::createFromFormat("YmdHis", $dateTimeString);
-        } else {
-            throw new ZugferdUnknownDateFormatException($format);
         }
+
+        throw new ZugferdUnknownDateFormatException($format);
     }
 
     /**
@@ -1715,7 +1725,9 @@ public static function isAllNullOrEmpty(array $args): bool
         foreach ($args as $arg) {
             if ($arg instanceof DateTime) {
                 return false;
-            } elseif (!self::isNullOrEmpty($arg)) {
+            }
+
+            if (!self::isNullOrEmpty($arg)) {
                 return false;
             }
         }