upgrade from 3.0.4 to 3.1.0 via FA website worked well. I like the new web display.
Note that the log messages showing on the FA site do not show the various apt-get package upgrade messages because those are not in the piaware log. So don’t panic if it looks like nothing is happening when you first submit the command. If you check /var/log/messages on your Pi you will see that the upgrade is progressing. Give it a few minutes to do its thing.
Some clean up afterwards may be required on your part, or not, depending on what modifications you have made. This upgrade modifies or replaces bunches of files so check those that you have modified. For example, /usr/share/dump1090-fa/html/config.js, I had to re-enter the Bing key and re-enable the ChartBundle layers.
Good job FA! two thumbs up.