Recently, people discovered a particular string of characters that caused iPhones to lock up and restart. Apple is working on an update to resolve this issue, but has detailed a fix that will let you re-open the Messages app if affected by the bug.
Apple said that users should open Siri, tell Siri to mark all messages as read, and then reply to the message that caused the issue in the first place.
Apple said that it is “aware of an iMessage issue caused by a specific series of unicode characters and we will make a fix available in a software update.”
The string of characters can also affect Snapchat and Twitter if sent via private message.
The bug itself seems to be nothing more than an inconvenience. There are, of course, fears that unscrupulous people could try to find ways to make it more malicious. But, for the moment, there’s nothing to really worry about.
If you want to take preventative measures, you can disable notification banners.
It is hoped that Apple will release a software update very soon.