Computer devices become obsolete in 5-6 years. It's from my own experience. But devices produced during last 5 years are in use. So a good quality website should work fine on all of them. If now is 2018, then this is the period from 2013 till 2018. Let's think about it. If there is a PC produced in 2013, it probably runs Windows 7, 8 or 10. In this case desktop browser would automatically update to the latest version. But what about phones and tablets…