[tryp4vps]

..... Therefore, this article says that Signal has encrypted chat so ISIS doesn't get tracked whenever they wanted to communicate. While on the other hand, Telegram doesn't have one since they can track down ISIS.

But in fact ISIS could still use secret chats on Telegram to communicate, so that their messages could get encrypted and would not get tracked.

And back to the topic for Whatsapp. I think for most other users, normal chats do not really need encryption. As far as I can remember, Whatsapp also did not have encryption for many many years, and just started introducing encryption on around 2016.