Not to be a wet blanket (and anyone that has more info please jump in) but I recall RJ stating that the LE v5 has a different VReg and it has a different pin-out. This means that the v5 has some circuit traces that are different when compared to the v4. The LE v4 cannot be upgraded to a v5 without major work. I sold some v4 kits and got the question of whether or not they could be upgraded from a prospective buyer and the prevailing answer from the group was a resounding "NO". If you have a v4 PCB, build it as a v4. If you want a v5 you need to start with a v5 PCB.
If I flubbed this please feel free to set me straight but this is how I recall it.
Thanks
Alan T