Google Duo works on iOS as well as Android and offers unlimited free video calling to anyone using the same app on their device. However, since its release, Google Duo has been blocked in Morocco
Duo is a video chat mobile app developed by Google was announced at Google I/O on May 18, 2016 alongside Allo, an instant messaging app. Duo launched in the United States on August 16, 2016 and globally a few days later. Duo quickly climbed to the number one free app on Google Play within two days of its initial release
It worked in Morocco for the first month before the National Telecommunications Regulatory Agency (ANRT) found a way of blocking it. It took the ANRT some time as the app uses a slightly different technology from the other VoIP apps - Skype, Viber and WhatsApp.
Alaa-Eddine Kaddouri, software architect and entrepreneur in the information and communications technology explained to Telquel.ma that it was technically "a little more complicated to block such communications," however he said that it was "quite possible".
Unfortunately for the ANRT, Moroccans took only a few days after its blocking of VoIP services to discover ways around the blockage by using a VPN.
The use of a VPN (Virtual Private Network) creates a tunnel on the network and overrides the limitations established by the ANRT. To use a mobile VPN, is extremely simple. Once downloaded and installed, VPN apps automatically configure the VPN. Once connected to a network, users place a call normally, whether you are connected over 3G / 4G or WiFi. The most sophisticated of the VPN apps have the ability to disguise the fact that they are a VPN and are therefore undetectable.