I’ve compile the Linux 3.10 kernel with HiFiBerry support. You can download the tar file from the HiFiBerry website. The archive includes the updated Raspberry Pi firmware for kernel version 3.10. Therefore it should work even on systems that run Linux 3.8 now. However I cannot guarantee, that it will work on all configurations. Therefore use it on your own risk.
Would this new kernel also work on Openelec or is it only for raspbian / raspify?
What combinations have been tested/ reported to work?
I tested it only on RaspyFi and Raspbia. However, if OpenElec uses a standard kernel, the chances are good, that it will work. You can make a backup of your SD card and then test it and report it here.