Beware of a strange glitch that’s being used right now to attack iPhone users. If someone send you a text message with the following text, it will force your iPhone to turn off, reboot, and then the iMessage app will become unusable until someone sends you another text.
لُلُصّبُلُلصّبُررً ॣ ॣh ॣ ॣ
From what I can tell, your iPhone will resume working after another message has been received. But until then, good luck… Apple, please do something to fix this!