When upgrading any software on your server, ensure that you test the new version thoroughly. We've taken all care in creating this Wizard, but it is your responsibility to ensure that the upgraded version will work correctly on your website.
Also, make sure you download the working copy from your server so that you don't upgrade the wrong copy of FormMail.
When converting from Matt's Perl FormMail, please note that only your recipients value is transferred across. For NMS Perl FormMail the recipients and allow_mail_to values are transferred across. The Wizard understands these values in many common formats.