Pro users gained the ability to see album artist names when browsing in MediaBrowser. Hardware Acceleration:

Serviio Pro license file is a distinct digital file with a .lic extension

The is a paid upgrade (typically around $25) that unlocks a suite of advanced features for power users. The primary differentiators are:

A: Yes. Your Pro license is permanent. As long as you have your .lic license file saved, you can simply reinstall Serviio and re-upload the file to unlock the Pro features again. This is why it's so important to keep your license file in a safe place.