We enhanced the banning system: when using user registration, we ban per IP as before. But we also added banning per username, so banned user cannot reconnect with the same username once banned.
He needs to create a new user and change his username to be able to be back.
Webrtc IP leaking
There is a leak in webrtc that allows (under circumstances) to get the real IP of an user, even if he’s behind a VPN
We used that technique for banning to get the real IP from an user even if he’s using a VPN. This technique may stop working soon since major browsers may correct the IP leaking from webrtc very soon.