I've been trying to install Pybossa and I've been trying to follow these steps from the documentation, and this link too (which they're the same).
when it comes to using this command pip install -r requirements.txt it keeps running some installations and then and error occurred :
ERROR: Could not find a version that satisfies the requirement jeepney==0.4 (from pybossa==3.1.2->-r requirements.t xt (line 3)) (from versions: none)
ERROR: No matching distribution found for jeepney==0.4 (from pybossa==3.1.2->-r requirements.txt (line 3))
this is what's inside requirements.txt : 
I don't know why this is happening as i'm following the documentation .. so i'd glade if anyone helped me.
I'm using :
- Ubuntu server 18.04
- python 2.7
- virtualenv
- PostgreSQL