Why did iMessage change from read to sent?

You can turn off the read receipt in the settings. After closing, whether you read the message will only show that it has been sent. It is a choice to protect privacy.

IMessage is an instant messaging software launched by Apple, which can send short messages, videos and so on. It has high security. Different from the SMS/MMS service of operators, users only need the data support of WiFi or cellular data network to complete communication.

On March 10, 2020, according to MacRumors, Apple is testing new features of iMessage, including mentioning "@" and withdrawing messages. These features may be released in iOS 14 as soon as possible.

relevant information

May 27th, 20 15, a bug in Apple's iMessages application may cause the iPhone to restart after receiving a special string message. The vulnerability was discovered by iPhone users on the news website Reddit. Whether the iPhone is running the latest version of iOS 8.3 or the old version of iOS system, this vulnerability will cause the phone to crash significantly.

However, according to the feedback from Reddit users, if the recipients were checking their messages at that time, the iPhone that received the messages would not be turned off. The iPhone crashed because this string of Latin and Arabic characters would cause errors in the notification banner.