As part of my work with a charity, I have been creating a website for them. To ensure browser compatibility, I have been using Browser Shots to preview the site in various browser configurations.
My query is regarding how much backward compatibility should be prioritized. Currently, I am aiming for the last 5 versions of major browsers such as Internet Explorer, Chrome, Firefox, Opera, and Safari. Is it necessary to support all five previous versions, or would ensuring compatibility with just the last two versions suffice? Some elements like rounded corners in CSS may not render correctly on older browsers, so should I make accommodations for them or simply display a message suggesting they upgrade their browser for optimal viewing?