With the release of the new Raspbian Stretch, they suggest that clean install would be better.
Because of this, I think I will reinstall HA.I will do All-In-One installation. Is there a way to implement Python 3.6.x with this new installation? If not, how to upgrade the Python on a new installation?
Thank you for your reply, I saw this post. Some people complain that something does not work and I hoped that maybe there is a way to install it with 3.6 right away.
Actually, I was able to do it. I removed 3.5 Python installation, installed Python 3.6.2 and, after that, installed All-In-One Home Assistant. When I check, HA uses Python 3.6.2.