At work, we spend a LOT of money with heroku every month. We really wanted to use Protobuffers (please let's not discuss that ;) ), which require HTTP 2 for the streaming stuff. So we talked with them and were like "heyy, we need this" and while they didn't explicitly say they weren't going to support it, the response basically boiled down to "yeah, i wouldn't be holding your breath" ;)