Version 3.1 brings two new backends, optional loudness and convolution filters, improvements in non-synchronised backends, enhancements, stability improvements and bug fixes.
**New Features**
-* A `sndio` backend gives Shairport Sync fully native synchronised output on OpenBSD and FreeBSD, thanks to the work of [Tobias Kortkamp (t6)](https://github.com/t6).
+* A `sndio` backend gives Shairport Sync native fully synchronised output on OpenBSD and FreeBSD, thanks to the work of [Tobias Kortkamp (t6)](https://github.com/t6).
* A `pa` backend now allows Shairport Sync to provide synchronised output on PulseAudio-equipped systems -- many desktop Linuxes use PulseAudio as their sound manager.
* Optional loudness and convolution filters can be incorporated in the audio processing chain, thanks to the fantastic work of [yannpom](https://github.com/yannpom).
* A volume-change program hook has been added to execute an application whenever the volume is changed.