The new feature of php7 upgrade is that mysql connection initialization database is not applicable. If there is a little more content, the connection configuration is messy, and it will be difficult to change all mysql to mysqli.
You can modify the corresponding php operating environment when running the website
Modification in Xiaopi Panel website management
This is a positive solution
Modifying in the panel operating environment does not take effect on the website, and modifying system environment variables is useless. Many answers are misunderstandings. The system variables correspond to the programs called by the system cmd. The environment of the website is related to the middleware. If you want to modify it, you must directly modify the middleware configuration to call different versions of php. The Xiaopi panel is the management middleware, but Considering that the direct modification in the multi-site running panel environment will not take effect, so set it separately under the website configuration .