The CMS Design System follows the 2% rule: we officially support any browser above 2% usage and the last 2 browsers versions for each browser as observed by analytics.usa.gov. Currently, the latest 2 versions of Chrome, Firefox, Safari, and Edge are supported.

The CMSDS is designed to be compatible with different operating systems and browser versions in order to provide a broad range of support. Progressive enhancement and graceful degredation methodologies are used to accomplish this.