Stylus pro 7900 / 9900 white ink help

[Garyetaylor]

hello, I have both the 7900 and the 9900, what is the difference between the wt7900 and the 7900, i mean I know it uses white ink but is there any hardware differences ? Reason I’m asking is I want to convert my 7900 to use white ink, I’m assuming the wt7900 and 7900 are technically the same, can the firmware be updated to the wt? Or is their something in the settings where you can customise your cartridges? Thanks in advance