We have just had a notification from one of our suppliers regarding a firmware update from Lexmark. If you like many people use refilled or compatible cartridges do not accept any updates from Lexmark, if you do accept this update then you will never be able to use anything but new genuine Lexmark cartridges for the life of the printer, once installed there is no going back. This applies to all Lexmark printers regardless of age.
Note, as Dell printers are made by Lexmark it may also apply to Dell.