Even if nothing had gone wrong technically, it's worth remembering that every time you change what a user has to do, you're creating slowdowns and glitches. It's true of E-tailers dealing with processors, programmers with APIs and customers with E-Commerce sites (or even brick-and-mortar stores): Move things around or change the way things work and you may impress some users with your shiny new features—but you will confuse and irritate people whose highly productive habits have stopped working. And to Sage Pay's credit, it eventually found a temporary workaround for that problem.
Officially, the processor insisted that problems never rose above the level of inconvenience (although merchants who complained about delayed settlements would use a stronger expression). But the company also built the system based on feedback from thousands of customers, showed it to focus groups and ran a live test site for weeks before throwing the switch on the upgrade. At least in principle, Sage Pay did everything right.
But after all the grumbling over the new system, Sage Pay did something very clever: It quickly retrofitted its old user interface with the new system's processing infrastructure. By Wednesday (Nov. 3) merchants were able to use the familiar interface again—after clicking past a note that warned: "This original version of My Sage Pay is provided for backward compatibility only. We cannot guarantee the availability of this version in the longer term. Please adapt your processes to work with the new interface at your earliest convenience."