Not long ago there was a thread about using 060 in a 040 slot. It was noted that the 060 has a extra "ring" of pins towards the core, that the 040 didn't have, so it would not be possible to upgrade from a 040 to a 060 but a 040 should still be able to be used in a 060 socket.
I knew one of the technicians at phase5, and they seemed very streamlined in their development so it wouldn't supprise me if they made the 040 and 060 slots compatible.
I have never been able to confirm any of this since I haven't tried to fit a 040 in my Apollo 060. Just be carefull with your purchase.
