jacko I tried to perform the upgrade on HawkHost shared hosting plan. They allow SSH access and I could install Composer with no problems. Following this guide: http://discuss.flarum.org/d/1331-flarum-0-1-0-beta-3-released I reached step number 7, where I got "Permission Denied" page with plenty of code.
jacko I run the upgrade again and it worked. I must have done something wrong. Lack of experience. 🙂