"Well, I worked at a HFT firm for a long time until last year, the firm places millions of trades per day and is among the most successful in the markets it trades. And what did we use? Only modern features. Lambdas, auto, unique_ptr, range-fors, even std::async -- everywhere in our code. "

FWIW, I have been on the industry only 3 years so far, but I also see modern C++ and boost everywhere. I'm aware of the obvious selection bias, but then again it also applies to the author: if a firm has to call an external consultant to make sense of their codebase, it wasn't probably very good to start with.