Good thing too
About time this happens!
The only people that 'should' be running processors that old are those running retro games / or possibly vintage applications, or a museum exhibit.
If that is the case then it is almost impossible to run your 'classic' / retro game or application on the current release anyway - all of the support software is almost guaranteed to be missing because the underlying API and libraries have changed (i.e. sound, window manager etc). So the chances are this won't affect you anyway, because you will either be running an older OS in a VM on top of both a newer version of Debian and more modern hardware...
Or you could be be running genuine vintage software on a genuine vintage machine (lets face it Debian released AMD64 support - i.e. machines with either AMD 64bit CPUs with AMD64 extension and all Intel CPUs with Intel 64 extension, and a common 64bit user space way back with the release of Debian 4.0 Etch in 2007)
A machine of that age is likely to be a museum piece - in which case run it with equivalent age software (and if you must connect it to the internet then please, please, make sure there is a decent firewall between it and the rest of the world!), so again you probably shouldn't be trying to install the latest version of Debian on it...
If you are still using a machine of that vintage for any other reason, chances are that you will do the environment a favour by replacing it with a more modern machine that will consume far less power to do the same job...
/Rattus