Ensure that you always keep the symbol-defs.html.cut file in the icons folder - otherwise this blocks publishing on the CMS.

Process to upload new icons

Load up the Icomoon select page in an incognito window. Pull the latest files from github for this repository.

Click the 'import icons' button on icomoon. Navigate to this repository, select and open the 'selection.json' file in the icons folder (of this repository).