Today, March 14, 2006, the second edition XForms 1.0 became a W3C recommendation. The intent of this 1.0 second edition is mostly to add clarifications and correct errors in the first edition.
Maybe the only really new feature is the introduction of an instance attribute on <xforms:submission>. An XForms form uses one of more XML documents called instances. Typically an instance is used to capture the data entered by the end-user in the form. An XForms submission can send an instance and receive back XML data that can be used in the form. This feature of XForms is very powerful and we use it in the XForms Instant Translation to do on-the-fly translation. With the new instance attribute introduced by the second edition, data that comes back doesn't necessarily have to replace the instance that was sent, but it can instead be stored in another instance. This attribute is already implemented in PresentationServer 3.0.
Part 1 introduced mostly features that have some equivalent with features from HTML. This part introduces completely new concepts that have no HTML equivalent.