Occurs when the version number of the form being opened is older than the version number of the form template on which it is based.
Assembly: Microsoft.Office.InfoPath (in Microsoft.Office.InfoPath.dll)
The developer attempted to bind the event in some location other than the InternalStartup method.
The VersionUpgrade event is not meant to be instantiated by the developer in form code. You should only add event handlers for form-level events from the Microsoft InfoPath design mode user interface. When you add an event handler to your form template from the design mode user interface, InfoPath generates code in the InternalStartup method of your form code file using the EventManager class and the member of the FormEvents class to bind the event to its event handler. For information on how to add event handlers in InfoPath design mode, see How to: Add an Event Handler.
An event handler for the VersionUpgrade event allows you to run code to update a form when the form template on which it is based has been upgraded since the form was last opened.
The VersionUpgrade event is bound using the VersionUpgradeEventHandler delegate.
This type or member can be accessed from code running in forms opened in Microsoft InfoPath Filler or in a Web browser.