To use expired cartridges, you do NOT need to downgrade your firmware, or buy new chips or anything like that.
Just remove the little battery on the main board, and put it back in.
Date will now say 2005 or something, so all cartridges will be "new". It's a 30 minute job, it's free, and well worth the hassle, as new chips is something you only need if you use aftermarket ink.
In the software, you can change the date forwards, not backwards, if you screw up and change year, printer will stop working (ours did).
Procedure:
1. Unplug printer from all electrical, and unplug firewire.
2. In the back, on the right, remove roll holder and cover.
3. Remowe firewire board.
4. Locate battery, remove it, put it back in.
5. Put everything back together.
6. Screws left over proves you did a better job than the factory
7. Good to go.
Only difference will be a few personal settings like margins and such that will be back to factory default.
I would not worry about the ink being a couple of years old, as long as it has not been opened for more than a few months. We have bought several sets of expired ink from our local supplier at half price... Brand new, sealed, never opened.