CB

Use a second CSS class to migrate fontawesome 4 usages to fontawesome 5. Add parameter to disable it as well just like jQuery migration. Once all of core usages have been migrated this can be changed to default disabled and eventually removed.

https://fontawesome.com/how-to-use/upgrading-from-4

Example migration for alternative styling to new naming convention:

.cb_template .fa[class*="-o"] should be attached to .cb_template .far, which ensures the correct font will be used for those styles. Others will just need flat out to duplicate some code, but can all be generated using SCSS.