By and large, most addons can seamlessly cope perfectly fine with handling either Font Awesome 4 or Font Awesome 5 icons. The markup and names of the font files are significantly different between 4 and 5, so the chances of conflicts or breakage are limited. Font Awesome 5 is the future and a growing number of addons are already being updated to use Font Awesome 5. With so many new icon designs and various other improvements, there are some great benefits of using Font Awesome 5 in websites today and version 5 has already been available for several months; giving developers ample time to test and update their addons.
For webpages that do not include Font Awesome 5 already, you can go to their website and click the ‘how to use’ link. There you will see a code snippet like this:
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.3.1/css/all.css" integrity="sha384-mzrmE5qonljUremFsqc01SB46JvROS7bZs3IO2EmfFsd15uHvIt+Y8vEf7N7fWAU" crossorigin="anonymous">
Copy and paste this into your RapidWeaver Page Inspector > HTML > Custom Header box.
You do not need to download or install any Font Awesome 5 files, unless you wish to host the icons yourself.
Then wherever you want to use Font Awesome 5 icons in your webpage, use the simple HTML code snippets available for every unique icon design like this:
<i class="fas fa-star"></i>
Sure, multiple versions of Font Awesome in the same webpage is not ideal from an efficiency standpoint. But the markup and font file names for version 4 and version 5 are different, so you should not encounter any problems with your newly added icons conflicting with existing ones that might be in the page already.