I've been getting a lot of emails from people recently and this also came up on the CFWebstore email list. Authorize.Net recently sent out an email to all their merchants about changes to the Transaction ID, that may effect shopping carts that store it as an integer. CFWebstore has always stored the Transaction ID for Authorize.Net (as well as other gateways) as a string field (varchar) so this does not effect anyone using any version of CFWebstore, your stores will continue to work just fine.