As a standard, we aim to build websites that display and perform well on the latest versions of Chrome, Safari, Firefox and Edge. This amounts to more than 95% of active browsers – by usage. The main reason for not supporting older browsers is that they do not support modern design and development techniques.
Though if required we can design and develop a website with support for any browser/version, though this either limits our approach regarding features or requires extended effort/cost.
As browsers are designed with backward-compatibility in mind, older sites need not worry about displaying or performing on newer browsers.