If you are asking if the notification that you receive when the battery level is 30% or lower can be removed, the answer is that it can't. For it to disappear you will have to charge the phone so the battery goes above 30%.
Not removeble unfortunately. Maybe Sony can remove it in a future update because it's very annoying. Both 30% and 15% notification. There's no need to tell people the battery of there phone is at 30 or 15%. One can tell by the symbol at the right top of the screen. And if people need the use of Stamina at the point of there battery being almost empty they can set this in the Stamina app. Like turn on Stamina at 15%.
