I received a text message on my mobile phone reminding me that the Android version has been upgraded. I want to ask, does it matter if I don't upgrade? Can it still be used without upgrading?

That's a system push message. If your mobile phone doesn't have root, don't brush it, it is recommended to upgrade. Because the system upgrade package is introduced to solve some problems and errors, the upgraded system will be optimized, such as power saving, and the system will occupy less resources because of algorithm optimization. . . . . .