I have it working with my Xperia 10 II and the most recent Firmware (4.4). The Guide isn’t completely accurate anymore because it’s for an firmware version that had a different GUI. The differences are not that big and with a bit of experimenting you should get it to work. If i remember correctly package for Firmware 3.3 has nowadays the problem that it always forgets the password. and that there is no aarch64 package for the 64bit devices. Nokius has more recent builds in his repository that are working fine with firmware 4.4. I’m not sure if IPv6 might be a problem.
I wish you the best of luck to get it working on your side.