When you encounter the prompt of "certificate expired" during installation, you can install normally with the following settings: advance the date of the mobile phone by one year and reinstall it. After the installation is completed, just call back the normal date. In addition, it is suggested that you can try to turn off certificate detection, enter the "Program Management" menu "Settings" of the mobile phone, set the "Software Installation Option" to "All Software" and set the "Online Certificate Check" to "Off" to install normally.