How to restore the old version after upgrading the mobile phone system

You can restore the old version by restoring factory settings.

Take the OPPO mobile phone as an example, the details are as follows:

1. First, open the "Settings" icon on the desktop of the mobile phone.

2. After clicking to enter, on the page that jumps out, select the "More" option under the "General" page.

3. After entering "More", click the "Restore Factory Settings" option at the top of the options.

4. Before restoring factory settings, you can back up your phone first and then click the "Reset Phone" option below.

5. After clicking "Reset Phone", the page for entering the password will jump out. At this time, just enter the set power-on password, so that the phone can be restored to the previous version.