Eastern European here, both Whatsapp is prevalent and Telegram is gradually gaining ground (although I use it from back to the start of 2016). Surprisingly to

Eastern European here, both Whatsapp is prevalent and Telegram is gradually gaining ground (although I use it from back to the start of 2016). Surprisingly to me as a techie, a lot of people outright demand you on Viber or you can't text them. I still refuse though because Viber is crap: it's ad-ridden and can't even sync chats properly when you install it on a new device.