Ernesto,
Thanks for the link, but it does not seem to be working for us. We need the forms we created in the past to stay the same, while the forms created after we publish to have the new changes.... all in the same document library.
We are using browser based forms... When we select the 'Do nothing (existing forms might not work properly)' option, the old forms are updated with the new changes after publishing.
Is this possible?