OpenSSL mitmproxy HTTP2 support

Hello,

I’d like to use mitmproxy to alter HTTP Referer.
The problem is that I constantly receive the following warning:

HTTP/2 disabled . OpenSSL 1.0.2+ required

Currently I have the following packages installed:

mitmproxy 0.18.1
cryptography 1.5.2
OpenSSL 1.0.2j
python 2.7.9-2+deb8u1

Does this mean I have to update OpenSSL in order to receive HTTP2 support?
What is the easiest way to get HTTP2 support?

I have read this article but I still can’t figure out how to make mitmproxy work with HTTP2.
https://cryptography.io/en/latest/installation/#using-your-own-openssl-on-linux

Thank you in advance!