The latest firmware for the base Z3100 does seem to be 7.0.0.3-7 and it appears to have been released on June 17 2009 although this is the first I've seen it. My printer reports 7.0.0.3 and not the final -7 designation as well. Looking the current firmware as I downloaded it and unzip'd it before install - it is7.0.0.3-5 and was dated May 2009.
Type: Firmware
Version: 7.0.0.3-7 (17 Jun 2009)
Operating System(s): Microsoft Windows 2000, Microsoft Windows Server 2003, Microsoft Windows Server 2003 for 64-bit Extended Systems, Microsoft Windows Vista, Microsoft Windows Vista (64-bit), Microsoft Windows XP, Microsoft Windows XP Professional x64 Edition
File name: TR12-MVL-U-7.0.0.3-7.exe (516 MB)
* You will be able to replace a cartridge that has run out of ink in the middle of a print without needing to cancel the print.
* When loading photo papers, the printer will ask if you want to cut the leading edge of the paper.
* You will be able to load 11-inch-wide rolls.
* A firmware upgrade will not delete custom paper presets from the printer.
* You will be able to assign an IPv6 address to the printer from the front panel.
* There will be a new option in the Paper menu to advance and reverse paper without cutting it.
Note: During the upgrade, the printer's front panel may display a white screen for two minutes before continuing with the upgrade process.
If your current firmware release is 6.0.0.8 or older, when you upgrade to release 7 all the job accounting data will be deleted. If you need to keep this information please go to the Accounting tab of the Embedded Web Server and use the Export to Excel feature to save the current accounting information in your computer.