Hello,I think the function that

bool QLowEnergyControllerPrivate::setSecurityLevel(int level)

should be public.

I'm developing a software to control BLE device for my computer.

It can't work normally if the SecurityLevel is low.

I should set it to medium.

I research your code about this,it seems that it's controlled by the qt automatically.

I hope it can control it by myself.

Because you know,sometimes the device may not request to increase the sercurity level automatically.