Is WAP still a relevant protocol stack? Please overlook any oversight. I couldn't find much recent material on the internet, and just had a networks course this semester. The wiki page mentions that as of 2013, it's usage has largely been absent. But I found a stack exchange thread dated 2011 that the WAP 2.0 is still in use. As of 2015, with the current crop of smartphones and high-speed 3g/4g services provided by the operators, is WAP still supported or used? And what version(s) exactly?

WAP is still used. I don't know which version it is. It's usage is really small. In our network it generates 200-300 times smaller traffic compared to the other mobile Internet traffic (http, ftp and other).

I don't know why it is still used. Maybe some companies have old devices which are using this protocol - like taxi, tracking, cash terminals, or other similar devices (this is just an example - I'm not sure if these devices actually use WAP).