Volumio2 - kernel sources?

Although I have seen earlier questions about kernel sources, I am afraid I also need to ask this…

I downloaded the “Volumio2 RC2 Hotfix 2016-07-01” from github.com/volumio/Volumio2,
which seems to run OK on my Raspberry PI 2 model B.
‘uname -a’ reports its kernel revision as:

Linux volumio 4.4.9-v7+ #884 SMP Fri May 6 17:28:59 BST 2016 armv7l GNU/Linux

I would like to add a new device driver to control a new DAC board. Earlier, I successfully developed and tested this driver with alsa on my same RPi-2 with a standard Raspbian 4.4y source-code distribution.

For exact kernel module version alignment, it seems to me that I should recompile my driver against Volumio’s 4.4.9-v7+ kernel source (or -at least- its kernel headers). However, I cannot find where to obtain that particular kernel source version (from Raspbian and/or Debian itself) and configuration. Can someone give me a correct pointer, e.g. some github repo with a specific version?
(Or, would my Rasbian-4.4 .ko modules and its dtoverlay integrate properly with Volumio2-RC2 ?)

thanks for your help,

We align the kernel with the latest raspbian release, so there are good chances that you can compile your modules against raspbian and make them work with volumio …
If not, you should be able to find everything you need here: