Tried 3.8, too buggy. So switched to 3.7.13 which works fine with file sources but the osmocom source block doesn't work. Tried setting rtl=0 1 2 and 3 but none work. (hackrf_info finds the hardware - I'm using a hack rf one).
Tried downgrading to 3.7.11 which also doesn't find the hardware but now substitutes a null source - which is a bit irritating so it initially looks like it's working until you notice there's no signal and go check your hardware... Help?