Hi Vlom,
When you get the message "Upgrade required" then you know for sure that the hub is set right and running, see the https://byteball.org/bb.
The link is to be added on wallet, under hub. The default is byteball.org/bb
I did follow the guide from portabella mostly but checked on other articles as well on how to install nodejs on raspberry since it's very important to install it right: http://thisdavej.com/upgrading-to-more-recent-versions-of-node-js-on-the-raspberry-pi/

$ sudo apt install nodejs
$ curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -
$ sudo apt install nodejs
$ node -v
v7.5.0
$ apt-get install node-sqlite3 git logrotate
$ git clone https://github.com/byteball/byteball-hub.git
$ cd ~/byteball-hub
$ npm install
$ nano conf.js
Edit the fields, add you domain and change from false to true for hub:

exports.port = 6611;
//exports.myUrl = 'wss://mydomain.com/bb';
exports.bServeAsHub = false;

$ node start.js

Please follow this guide for letsencrypt: https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04
and tonych's guide of course: https://github.com/byteball/byteballcore