with the ubuntu 19.10 kernel now fully supporting the pi4 (and thanks to the holidays 
), i invested a little time to switch the kernel snap of my core18 image over to it (the snap is still called “linux-raspberrypi-org” so there wont be any upgrade path to the official image, but it is now at least built from the same source the official kernel will use later)
note that there is no way to upgrade to that new image, you need to completely re-flash your SD card if you were using the older one (once using this image you will be able to “snap install --dangerous linux-raspberrypi-org_*_armhf.snap” later in case i provide an updated kernel snap though)
the new image is in the usual place at https://people.canonical.com/~ogra/snappy/raspberrypi4/core18/
the snaps it was built from are in the snaps/ subdir, the old image is still available under old/ for people that want to use the actual raspberrypi.org kernel.
note: this fixes mir-kiosk support !