Deque Systems, Inc published EN 301 549 v4.1.1 in an article by Matthew Luken and Glenda Sims covering timelines, changes, and what to do next to achieve conformance.

Deque (pronounced dee-cue) is a web accessibility software and services company, and our mission is Digital Equality. We believe everyone, regardless of their ability, should have equal access to the information, services, applications, and everything else on the web. We work with enterprise-level businesses and organizations to ensure that their sites and mobile apps are accessible. Installed in 475,000+ browsers and with 5,000+ audit projects completed, Deque is the industry standard.