How is WCAG 2.0 different from WCAG 1.0?
Generally, WCAG 2.0 applies broadly to more advanced technologies; is easier to use and understand; and is more precisely testable with automated testing and human evaluation. The fundamental issues of Web accessibility are the same, though there are some differences in the approach and requirements between WCAG 1.0 and WCAG 2.0. See How WCAG 2.0 Differs from WCAG 1.0 for details such as the changes in requirements.