There doesn't seem to be a newer kernel than the mainline repo in proposed (4.4.0-38) but I was able to verify this using the 4.4.0-41 kernel in the canonical-kernel-team PPA.
There doesn't seem to be a newer kernel than the mainline repo in proposed (4.4.0-38) but I was able to verify this using the 4.4.0-41 kernel in the canonical- kernel- team PPA.