If you are using Sierra most things will remain unchanged in High Sierra. Here is a link to the comparison and what to expect:
https://www.macworld.co.uk/review/mac-software/macos-high-sierra-vs-macos-sierra-3660082/

https://www.roaringapps.com has an extensive compatibility catalog where you can look up most apps and find out which OS they are/aren't compatible with and what problems others have had