Why does Baidu know that the short message answers I receive are often garbled?

Due to the following reasons, the received SMS appears garbled:

1. The format entered by the sender user is incorrect;

Second, the version of the receiver's mobile phone system may be too old, resulting in the abnormal display of the received message. Please upgrade your mobile phone operating system.

3. Pictures sent online or ringtones downloaded, but this format is not supported by mobile phones.