I’m currently going through the time-taking process of updating all themes from Font Awesome 4.7.0 to 5.9.0. A ton of changes are needed for each theme, so it will take a while. The current status is that Gridzone, Minimer, Readline, Stylizer, Curver and Boxstyle are finished and now running FA 5.
Stay tuned as I work through all the rest of the themes.
Update:(2019-07-29) All 12 free themes are now using FA 5.9.0.
Update 2:(2019-07-30) All premium themes updated as well.