Apple has released a patch that will fix the so-called 'Telugu bug' on iOS, MacOS, tvOS and WatchOS. When users receive a message or notification that contains a certain Indian character, the app crashes and becomes unusable. In some cases, the bug even results in the device entering a bootloop.
https://www.notebookcheck.net/Apple-releases-patch-to-fix-the-Indian-Telugu-bug-on-all-platforms.284814.0.html