Wouldn't secure Wire[1] be a better replacement?
It's crypto-audited[2], open-sourced[3], has native mobile clients[4], Swiss based[5], and pretty well known[6].
[1] https://wire.com
[2] https://techcrunch.com/2017/02/10/messaging-app-wire-now-has...
[3] https://medium.com/@wireapp/wire-server-code-now-100-open-so...
[4] https://github.com/wireapp