diff --git a/src/Header/AbstractAddressList.php b/src/Header/AbstractAddressList.php
index 4ccd38bb..87f76c77 100644
--- a/src/Header/AbstractAddressList.php
+++ b/src/Header/AbstractAddressList.php
@@ -58,7 +58,12 @@ public static function fromString($headerLine)
         // split value on ","
         $fieldValue = str_replace(Headers::FOLDING, ' ', $fieldValue);
         $values     = explode(',', $fieldValue);
-        array_walk($values, 'trim');
+        array_walk(
+            $values,
+            function (&$value) {
+                $value = trim($value);
+            }
+        );
 
         $addressList = $header->getAddressList();
         foreach ($values as $address) {