This release consists for the most part of bug fixes that target areas such as PBAP, AVRCP and GATT.
Feature-wise a notable change is btmon support for vendor diagnostic messages which will be debuting with the 4.4 Linux kernel release. This feature will allow e.g. LMP tracing with specific controllers. For now there is preliminary support for Intel and Broadcom based controllers. You can already now enable and experiment with the feature using the bluetooth-next kernel tree by writing “1″ to the “vendor_diag” file in debugfs.