There's a nasty exploit in early versions of iOS 11 that can cause an iPhone or iPad to crash when sent a specific character from the Telugu language of India in Messages or several popular third-party apps like WhatsApp, Outlook, and Facebook Messenger. This bug not only causes a Springboard crash (reboots your Home screen), but prevents you from opening the app that received a message with that character again because the app is continually trying to load the message.
The good news is that you're not helpless when dealing with this bug.
Update your operating system
Apple has a software update to fix this issue: You'll just need to update your phone to iOS 11.2.6 and later.
How to fix the Telugu character bug on iPhone and iPad
If you've been struck by this bug and can't update your phone for whatever reason, you can still fix it by having a friend send you a sort of "rescue message" in a different thread and tapping on that notification.
- Tap on the notification for the "rescue message" you received.
- Hit the back button in your messaging app to get back to your list of chat threads.
Delete the thread we the Telugu character in it.
This should fix the problem. If you're trying to fix this bug in a third-party app on your iPhone or iPad, you can also just uninstall the app, then reinstall it. After doing that, delete the offending thread when it appears in your list of conversations.
If you've got any questions about fixing the Telugu character bug, let us know in the comments.