Icon Upgrades
Icons added with the Icon Chooser in the block editor are not automatically upgraded. Read on to understand why.
For the following scenarios, suppose you're using a Kit set to use the "Latest v7" of Font Awesome, and the latest happens to be verson 7.0.0.
When using the Icon Chooser in the block editor
Suppose you add an icon to a page using the Icon Chooser in the block editor. The icon is added as an inline SVG, as it's defined in Font Awesome 7.0.0.
Then, let's say we release Font Awesome 7.2.0 and change the design of that icon. You prefer that newer design. Even though your Kit is set to use "Latest v7", your web page will continue to show the version of that icon as it was in Font Awesome 7.0.0.
If you want the newer icon design, you'll need to manually re-add the icon to your page using the Icon Chooser.
When using <i> tags or [icon] shortcodes
As long your Kit is being loaded on the page, and isn't being undermined by conflicting versions of Font Awesome loaded by other plugins or themes, then all icons will be rendered as their 7.2.0 versions. Thus, the icons are automatically upgraded.