You can mitigate a downgrade to 2G by using a VPN and a VOIP app like Whatsapp or Viber. Call quality would be abysmal on EDGE. I haven't seen any stock confi

You can mitigate a downgrade to 2G by using a VPN and a VOIP app like Whatsapp or Viber. Call quality would be abysmal on EDGE. I haven't seen any stock configuration of iOS that permits you to disable 2G. Using 3G or LTE wouldn't help someone trying to evade a state or higher law enforcement organization, since all they need to do is use the cellular provider's Lawful Intercept capability somewhere in the packet core, such as the GGSN (for metadata) or at a tower's next IP router (for call content). I think the purpose of this guide was primarily for border crossings. Filippo almost certainly gets hassled at borders, as many security professionals do. His comment about the Great Firewall was more likely about accessing an unrestricted internet, and less as an phone call anti-surveillance measure.