I was not talking about "outdated" versions of IE (although IE9 supports HTML5 and CSS3 to some degree so it is not so outdated as one might think). Also, it is a built-in browser.
I meant Webkit-based browsers and Firefoxes that are over 3-5 years old. What about Android phones with firmware without updates? What about smart TVs?
> I'm not sure why we are all trained to think that anything we build has to be compatible with old browsers
Because compatibility was one of the ideas behind HTML. Because there are less developers than users so it is easier to solve compatibility problems at their side.
I meant Webkit-based browsers and Firefoxes that are over 3-5 years old. What about Android phones with firmware without updates? What about smart TVs?
> I'm not sure why we are all trained to think that anything we build has to be compatible with old browsers
Because compatibility was one of the ideas behind HTML. Because there are less developers than users so it is easier to solve compatibility problems at their side.