By default, LiveCycle Designer ES uses a new encoding format that uses the XFA JavaScript function xfa.record.saveXML() to produce XML encoded data. However, you can still use the legacy encoding format that uses the old function xfa.datasets.saveXML(). For example, you may be processing forms with barcode data by using an application that can only parse the old XML format.
The legacy encoding format is used in paper forms barcode XML scripts in LiveCycle Designer 7.0 to 8.0. When you open a form that contains the legacy encoding format, the Use Legacy Format option is selected automatically.
See also 

To use legacy encoding format