According to 9to5Mac, the bug involves a specific text string in the Sindhi language. When a device with Apple’s mobile OS gets a notification of a text with this specific string, the result is a number of odd behaviours. The device in question could outright crash, or it could suddenly stop responding to touch input. Although this is regarded as an iOS issue, it is able to affect iPhones, Apple Watches, iPads and even Macs. As all you need to trigger the iOS bug is a notification containing the string, it could basically come from everywhere. 9to5Mac reports that it originated from a Telegram group, but has since spread to Twitter and other social media platforms. An Italian flag emoji was also thought to be a part of the bug-inducing string initially.
— EverythingApplePro (@EveryApplePro) April 23, 2020 So far, Apple has yet to issue a fix for this bug. It’s also worth noting that this bug doesn’t affect devices running iOS 13.4.5, but that version is still in beta. This also isn’t the first time texts have crashed iOS. Back in 2018, a specific Telugu character held this power over the Apple mobile operating system. And going further back to 2015, this happened thanks to a string of Unicode text. (Source: 9to5Mac)