diff --git a/components/libraryadmin.php b/components/libraryadmin.php
index 0c15a06884a27386d4606c9558d428bbe4efa058..0517381ace4c9f44a6e236eb5e2d3f2029dd601a 100644
--- a/components/libraryadmin.php
+++ b/components/libraryadmin.php
@@ -16,7 +16,7 @@ function fetch_isbndb_data($isbn) {
 
 function valid_isbn($isbn) {
 
-        return Validate_ISPN::isbn($isbn);
+        return (new Validate_ISPN)->isbn($isbn);
 }
 
 if ($session->groups[$permission]) {
diff --git a/lib/Validate/ISPN.php b/lib/Validate/ISPN.php
index 78c9c3dcf67fd18d5f259c4dc209d07b9a03ff64..bb6178567619e3663ba0c646d16a222e82dfb781 100644
--- a/lib/Validate/ISPN.php
+++ b/lib/Validate/ISPN.php
@@ -141,7 +141,7 @@ class Validate_ISPN
 
         // Requires base class Validate
         require_once 'Validate.php';
-        return Validate::_checkControlNumber($isbn, $weights_isbn, 11, 11);
+        return (new Validate)->_checkControlNumber($isbn, $weights_isbn, 11, 11);
     }
 
 
@@ -172,7 +172,7 @@ class Validate_ISPN
 
         // Requires base class Validate
         require_once 'Validate.php';
-        return Validate::_checkControlNumber($issn, $weights_issn, 11, 11);
+        return (new Validate)->_checkControlNumber($issn, $weights_issn, 11, 11);
     }
 
     /**
@@ -212,7 +212,7 @@ class Validate_ISPN
 
         // Requires base class Validate
         require_once 'Validate.php';
-        return Validate::_checkControlNumber($ismn, $weights_ismn, 10, 10);
+        return (new Validate)->_checkControlNumber($ismn, $weights_ismn, 10, 10);
     }
 
     /**
@@ -349,7 +349,7 @@ class Validate_ISPN
      * @param array $weights holds the weight that will be used in calculations for the validation
      * @return bool    true if number is valid, otherwise false
      * @access public
-     * @see Validate::_checkControlNumber()
+     * @see (new Validate)->_checkControlNumber()
      */
     function process($data, $length, &$weights, $modulo = 10, $subtract = 0)
     {
@@ -365,7 +365,7 @@ class Validate_ISPN
 
         // Requires base class Validate
         require_once 'Validate.php';
-        return Validate::_checkControlNumber($data, $weights, $modulo, $subtract);
+        return (new Validate)->_checkControlNumber($data, $weights, $modulo, $subtract);
     }
 }
 ?>