There are a few areas of the Oranged Software website that you may not have noticed.

The Studiometry archives contain almost every single version of Studiometry that has been released. If you ever need to download an older version of Studiometry, the archives are available 24 hours a day, 7 days a week.
Studiometry Archives

If you ever lose your serial number(s) or would like a consolidated list of all of your numbers, you can use the Serial Number Lookup page. This page will give you access to Studiometry serial numbers all the way back to version 2. The form will send your serial numbers to the registered email address used when purchasing the licenses.
Serial Number Lookup