Do you use Signal, a free and open-source messaging app for encrypted voice calls and instant messages developed by an independent non-profit organization?  Signal is a state-of-the-art app for private and secure communications. But as its popularity surged recently, we have observed its blocking in several countries.  Check out this article posted here: https://ooni.org/post/2021-how-signal-private-messenger-blocked-around-the-world/.  What messaging app do you currently use? Please comment.