diff --git a/SoObjects/SOGo/WORequest+SOGo.h b/SoObjects/SOGo/WORequest+SOGo.h
index e06df0aca..a9d25712d 100644
--- a/SoObjects/SOGo/WORequest+SOGo.h
+++ b/SoObjects/SOGo/WORequest+SOGo.h
@@ -37,6 +37,7 @@
 - (BOOL) isIPhoneAddressBookApp;
 - (BOOL) isAndroid;
 - (BOOL) isMacOSXCalendar;
+- (BOOL) isThunderbird;
 
 @end