Use this dialog box to update forms that were created in LiveCycle Designer ES version 6 to version 7. Updating older forms will result in the shifting of some text, which may require manual adjustment. In addition, script handling of enter and exit events on drop-down list boxes is affected. If the older form will be viewed primarily with Acrobat 7.0.5 or Adobe Reader 7.0.5 or later, use this Compatibility tab to update the form to version 7.
If you open a form from an earlier version of LiveCycle Designer ES, the text formatting rules are different.
If you open a form from an earlier version of LiveCycle Designer ES, the behavior of the enter events on the form is different. In version 7, the first time a user clicks in a drop-down list, an enter event is sent with the reenter property set to false. If the user clicks in the field again or presses the Enter key, another enter event is sent with the reenter property set to true.
To use the version 6 event handling rules, click Revert Event Model. For example, if you have a form that was created in LiveCycle Designer ES version 6, and you want to download data from the server only once on the first enter, you may want to keep the old event model or revert to the old event model.

Compatibility tab (Form Properties dialog box)