My firmware is out of date. Pioneer has v2.003 available for download, but the link on the website is to a .ZIP file called "110".

Is this by design or is the link on the site messed up? Is the firmware between the 110 and the 120 interchangable?

Thanks yo.

I think the link is correct. The file is ZVICZ110.zip. The update has a folder of the same name. The Z120 is the same hardware as the Z110. So, while the firemware are not "interchangable", there is a migration path from Z110 to Z120 (and, to some extent, Z130 with a slightly reduced set of features).