Bluetooth version 1.2 Introduction of adaptive frequency hopping. Compared to version 1.1, there is less interference with radio frequencies. Bluetooth Version 2.0 with Enhanced Data Rate (BT2.0 +EDR) When Bluetooth 2.0 is used with EDR, there is longer battery life and an improvement to duty cycles. Bluetooth Version 2.1 (+EDR) Introduction of simple pairing to allow a compatible phone to pair with the headset, through a simple confirmation, without a pass key. Bluetooth v4.0 Improved performance on signal transmission. The Bluetooth connection is more stable and less susceptible to interference. Bluetooth profiles are not tied to Bluetooth versions. For example, Bluetooth version 1.2 (and higher) supports A2DP, but not all Bluetooth 1.2 or Bluetooth 2.0 devices support A2DP. Manufacturers decide which profiles to support, according to the application and required profiles.