BlueZ 5.88: SimpleBLE's contributions

TLDR: BlueZ 5.88 is out, with 26 commits from SimpleBLE. Linux applications can now tell which devices accept connections, read the role and parameters of an LE connection, and use the bearer interfaces without experimental mode.

BlueZ is the Bluetooth stack for Linux. Every Linux application that uses Bluetooth goes through it, SimpleBLE included. When an application needs something BlueZ doesn't offer yet, we add it to BlueZ itself, so every application on Linux gets it.

With BlueZ 5.88, applications can pick out the peripherals they can connect to, and skip beacons and broadcasters, with the new Connectable property. The new Role property reports whether the remote device is the central or the peripheral of an LE connection, so an application that acts as both can tell an incoming connection from one it opened. Applications can also read the interval, latency, supervision timeout and subrate of an LE connection to estimate throughput and latency, or to confirm that a connection update took effect. And the bearer interfaces, which handle the LE and BR/EDR links of a dual-mode device separately, are now stable and no longer need bluetoothd in experimental mode.

The release also fixes discovery getting stuck when a request to stop it fails (bluez/bluez#2547), and advertising breaking when an application exits while registering an advertisement (bluez/bluez#969, which we reported in 2024). Related kernel patches, including the one the connection parameters need on most controllers, are in bluetooth-next and headed for an upcoming Linux release.

Thanks

Thanks to Luiz Augusto von Dentz, who reviewed and applied all of these patches, and to Marcel Holtmann for the 5.88 release.

If you are building Bluetooth into a commercial product and need help with the integration, get in touch.