Italian blog Mobile World found a critical error in release build for iOS and macOS 11.2.5 High Sierra 10.13.3. If you insert a strange Indian character (this is జ్ఞా) in any standard application, it will crash and close or even reboot the device in the case of iPhone. Bug works with third-party apps like Facebook Messenger and WhatsApp.
Because of the symbol apps can not start and remove it can be problematic if no other devices nearby. Or you can try to delete the correspondence with this sign after you send the message with any other text. So think before «joke» on your friends. In the beta version of iOS 11.3 error is not running, so the fix is to either wait with her or with the intermediate version 11.2.6.
This is not the first (and probably last) time a text message or links to «kill» the Apple device. Just last month, the link (this — iabem97.github.io/chaiOS) interfered with normal work in iOS 11.2.5 bug was removed. But that’s not all. In 2015 was the text that did tend to kill the Messages app, and in 2016 a 5-second video forced to suffer iPhone owners.