In 'What's new in WCAG 2.1?' Ricky Onsman from Intopia Digital explores the WCAG 2.1 extensions to WCAG 2.0:
"It doesn’t replace WCAG 2.0 in the way WCAG 2.0 replaced WCAG 1.0, but it extends it to cover factors affecting accessibility for some users that were not covered in 2.0.
In particular, WCAG 2.1 provides one new Guideline – Input Mechanisms – and 17 new Success Criteria to better address some of the needs of people with disabilities accessing web content on mobile devices, people with low vision, and people with cognitive or learning disabilities.
These additional Guidelines and Success Criteria address the reality that mobile devices are not only more ubiquitous than they were when WCAG 2.0 was released, but are more complex, come with a greater range of differences from device to device, and have become more critical to negotiating daily life."https://intopia.digital/articles/whats-new-in-wcag-2-1/