Originally Posted by mvs
Please create a dev copy of your production store and test the upgrade there.
Just to be sure that it will works.
In case of any issue appears, please write the description of the problem here, with screenshots, logs files if possible. Or you can contact our support team.
I'm not a developer and have no idea how to create a dev copy. So far, x-cart was pretty good at just suggesting upgrades that are stable and not disruptive. 5.4, I suspect was not supposed to be out for general use yet.
Some of the problems were compatibility. Some features not working. To be honest, perhaps the major problem was the offensive comments added to orders and contact forms.
Support managed to restore 5.3, but we lost 5 days worth of order data, a number of blank contact forms to chase down, and time spent filtering stuff out that customers shouldn't see. (ex; "Your wallet is getting fat").
Just realized that he post I responded to was kind of old. Sorry.