Don't have Telegram yet? Try it now!
https://nokiapoweruser.com/windows-10-phones-build-12534-leaks-in-video-check-the-spartan-new-mail-messaging-contacts-calendar-apps-in-action/
Windows 10 Phones Build 12534 may be the second preview build. Spartan, new Mail, Messaging, Contacts, Calendar apps in action