Everything has changed since it was first received, and we worked to use HTTP / 2 in Akka HTTP. Akka HTTP became the default backend for Play in version 2.6, so now it can be used.
Documentation: https://www.playframework.com/documentation/2.6.x/AkkaHttpServer#HTTP/2-support-(experimental)
Please note that since this comment was written (in early July 2017), HTTP / 2 support is still experimental, which means that there are a few missing bits that we know that we need to implement (and they will appear in the coming weeks; at the same time, community feedback using it in the real world would be very valuable, thanks!)
Konrad 'ktoso' Malawski
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