Is Bluetooth 5 compatible with 4.x? That is, can a Bluetooth 4.x Central connect to 5 Peripheral (or vice versa)? Does anybody know the power usage (idle, adve

Is Bluetooth 5 compatible with 4.x? That is, can a Bluetooth 4.x Central connect to 5 Peripheral (or vice versa)? Does anybody know the power usage (idle, advertising, data transferring, etc.) of BT 5 compared to BT 4.x LE? Thanks