Epson regularly change their printers so that they will work only on a newer version chip.
This means that a new printer may not work with an older version of the cartridge making it very important to choose the correct generation of chip for your printer. Obviously Epson want you to buy original cartridges and try to make it as difficult as possible for people to use compatibles.
If you want to buy these cartridges, make sure you firstly check in the description to ensure that your printer type is there. If in doubt – just ask!