Doc : Should we really mention Debian Jessie compat ?

I am seeing that funkwhale is targeted at Python 3.6, and seem to work on Python 3.5.

Is the behaviour with Python 3.4 something tested ? If no, we better remove the mention in debian install doc stating

this guide targets Debian 9, which is the latest debian, but should work similarly on Debian 8.

Debian 8 has python 3.4 only.