In order to combat software piracy, Microsoft developed a validation system. When you try to download updates or add-ons from their website, a pop-up box asks you to install a piece of software that validates the software that you have on your computer as a “genuine Microsoft product.” If you have a pirated or illegal copy of the Microsoft program, then you will not be able to get the updates or add-ons. It’s not that the software became illegal or pirated overnight, but that it never was legitimate legal software and when you try to install updates or add-ons it just shows what the software is in reality. The same is true about antichrists. John says that these people were never true followers of Christ to begin with and so when they left the assembly of believers, they are showing what they really are.