An operating system installation that saves all personal system settings, file locations, and applications from the older OS version is referred to as:
Answer Description
An operating system (OS) upgrade will replace the product with the newer version, leaving files and applications untouched.
Wikipedia
Upgrading is the process of replacing a product with a newer version of the same product. In computing and consumer electronics an upgrade is generally a replacement of hardware, software or firmware with a newer or better version, in order to bring the system up to date or to improve its …
Upgrade - Wikipedia, the free encyclopedia