diff --git a/Inpsyde/Sniffs/CodeQuality/DisableMagicSerializeSniff.php b/Inpsyde/Sniffs/CodeQuality/DisableMagicSerializeSniff.php
index 99bfaf0..750119b 100644
--- a/Inpsyde/Sniffs/CodeQuality/DisableMagicSerializeSniff.php
+++ b/Inpsyde/Sniffs/CodeQuality/DisableMagicSerializeSniff.php
@@ -43,7 +43,8 @@ public function process(File $phpcsFile, $stackPtr): void
         if (in_array($name, $this->disabledFunctions, true)) {
             $phpcsFile->addError(
                 sprintf(
-                    'The method "%s" is deprecated, please use __serialize and __unserialize instead.',
+                    'The method "%s" is deprecated, '
+                    . 'please use __serialize and __unserialize instead.',
                     $name
                 ),
                 $stackPtr,
diff --git a/Inpsyde/Sniffs/CodeQuality/DisableSerializeInterfaceSniff.php b/Inpsyde/Sniffs/CodeQuality/DisableSerializeInterfaceSniff.php
index 7784eed..5dad6ed 100644
--- a/Inpsyde/Sniffs/CodeQuality/DisableSerializeInterfaceSniff.php
+++ b/Inpsyde/Sniffs/CodeQuality/DisableSerializeInterfaceSniff.php
@@ -11,7 +11,7 @@
 class DisableSerializeInterfaceSniff implements Sniff
 {
     /**
-     * @return list<int>
+     * @return list<int|string>
      */
     public function register(): array
     {
@@ -33,7 +33,7 @@ public function register(): array
     public function process(File $phpcsFile, $stackPtr): void
     {
         // phpcs:enable Inpsyde.CodeQuality.ArgumentTypeDeclaration
-        $tokenCode = $phpcsFile->getTokens()[$stackPtr]['code'];
+        $tokenCode = $phpcsFile->getTokens()[$stackPtr]['code'] ?? null;
         $find = ($tokenCode === \T_INTERFACE)
             ? ObjectDeclarations::findExtendedInterfaceNames($phpcsFile, $stackPtr)
             : ObjectDeclarations::findImplementedInterfaceNames($phpcsFile, $stackPtr);
@@ -43,7 +43,8 @@ public function process(File $phpcsFile, $stackPtr): void
         }
 
         $phpcsFile->addError(
-            'The Serializable interface is deprecated, please use __serialize and __unserialize instead.',
+            'The Serializable interface is deprecated, '
+            . 'please use __serialize and __unserialize instead.',
             $stackPtr,
             'Found'
         );
diff --git a/tests/unit/fixtures/disallow-magic-serialize.php b/tests/unit/fixtures/disallow-magic-serialize.php
index c66710e..0ed833c 100644
--- a/tests/unit/fixtures/disallow-magic-serialize.php
+++ b/tests/unit/fixtures/disallow-magic-serialize.php
@@ -4,7 +4,6 @@
 
 class Foo {
 
-    // @phpcsErrorOnNextLine
     public function __serialize(): array
     {
         return [];
@@ -37,7 +36,6 @@ public function wakeup(): array
         return [];
     }
 
-    // @phpcsErrorOnNextLine
     public function __unserialize(): array
     {
         return [];
diff --git a/tests/unit/fixtures/disallow-serialize-interface.php b/tests/unit/fixtures/disallow-serialize-interface.php
new file mode 100644
index 0000000..1b7ab1f
--- /dev/null
+++ b/tests/unit/fixtures/disallow-serialize-interface.php
@@ -0,0 +1,58 @@
+<?php
+
+// @phpcsSniff Inpsyde.CodeQuality.DisableSerializeInterface
+
+// @phpcsErrorOnNextLine
+class One implements Serializable {
+
+    public function serialize()
+    {
+        return null;
+    }
+
+    public function unserialize($data)
+    {
+    }
+}
+
+// @phpcsErrorOnNextLine
+$x = new class implements Serializable {
+
+    public function serialize()
+    {
+        return null;
+    }
+
+    public function unserialize($data)
+    {
+    }
+};
+
+class Three {
+
+    public function serialize()
+    {
+        return null;
+    }
+
+    public function unserialize($data)
+    {
+    }
+}
+
+// @phpcsErrorOnNextLine
+interface Two extends Serializable {
+
+}
+
+class Four {
+
+    public function __serialize()
+    {
+        return null;
+    }
+
+    public function __unserialize($data)
+    {
+    }
+}