The more things change, the more they stay the same. When Apple released iOS 11 a few years back, the company had a serious issue revolving around text messages and foreign language character sets.
In that earlier case, the problem revolved around a certain string of Sindhi characters that had the result of locking the OS up and causing the device to crash.
These 'text bombs' are not just annoying, they can be absolutely crippling. After all, you don't even have to read the message, it just has to be sent to your phone. That means that anybody who knows the poison sequence can lock your phone up indefinitely.
A similar problem has resurfaced, impacting any device running iOS version 13.4.1 or earlier. The company is currently working on a fix. The latest beta version of the code, 13.4.5 has what appears to be a viable fix for the issue.
Unfortunately, Apple hasn't given a firm ETA when the fix will be made available to the general public, and the only other possible defense users are offering to each other is to temporarily disable notifications. While this doesn't prevent the lockup issue in every case, it does seem to help. So if you're currently experiencing what appear to be random lockups of your phone and you haven't been able to trace them back to a root cause, this could be the reason. If so, then disabling your notifications until the bug fix is available might at least make your phone a bit more stable.
All that to say, this isn't the first time Apple's products have encountered an issue like this, and it almost certainly won't be the last. The company is hard at work on a fix though, which should be available soon.
