diff --git a/include/class.auth.php b/include/class.auth.php
index e320a4f5ec384bfa16618c155d952973b4397c10..30a4290b64ca5e4d12909f69108dcc81dbc593ff 100644
--- a/include/class.auth.php
+++ b/include/class.auth.php
@@ -1,6 +1,8 @@
 <?php
 
 interface AuthenticatedUser {
+/* PHP 5.3 < 5.3.8 will crash with some abstract inheritance issue
+ * ------------------------------------------------------------
     // Get basic information
     function getId();
     function getUsername();
@@ -20,6 +22,7 @@ interface AuthenticatedUser {
     // Signal method to allow performing extra things when a user is logged
     // into the sysem
     function onLogin($bk);
+ */
 }
 
 abstract class BaseAuthenticatedUser
diff --git a/include/class.client.php b/include/class.client.php
index 746b5e63dee72a9533630c6df394bebf7e87646c..1c7bdcfa846660b304344a6ce5392db288b750ab 100644
--- a/include/class.client.php
+++ b/include/class.client.php
@@ -427,11 +427,14 @@ interface EmailContact {
 }
 
 interface ITicketUser {
+/* PHP 5.3 < 5.3.8 will crash with some abstract inheritance issue
+ * ------------------------------------------------------------
     function isOwner();
     function flagGuest();
     function isGuest();
     function getUserId();
     function getTicketId();
     function getTicket();
+ */
 }
 ?>