It's not that super secret. If you register on the Panasonic web site, you can download it yourself. It's at www.btsdealer.com
IF YOU ARE NOT IN THE UNITED STATES IGNORE THE REST OF THIS!!!
I'm not sure, but I think you can go from v1 to v3 directly in a TA-824. Here's a link to my website for v3. http://www.public.carl.airpost.net/TA-824/
There are two pieces, the v3 tool and the v3 files. Download the file, save it somewhere you keep track of, then download the tool. Install and start the tool, the programmer code is INSTALLER, and click on HELP Help. Allow the ActiveX content and click on Program Utility, tab 8.1. These are the software upgrade instructions.
Just for safety, back up your data. In a nutshell, you run the upgrade, find the file, and the system will install the firmware, then convert your data. It's all automatic, but the end of the instructions will tell you what to do if something happens.
Let me know how it worked.