Previous versions of the Vanderbilt ultrasoft pseudopotential package had names like a7.3.1, where 731 is a version-number sequence.
The links below resolve to a files with names like a731.tgz, each of which is a tarred-and-gzipped archive of an earlier distribution. To access the archive, save the file, then 'gunzip' and 'tar xf'.
Newer versions 733 and subsequent have names like uspp-734. These are archived here.
For older (pre-5a.1.2) versions, contact dhv@physics.rutgers.edu.