I'm not sure about the designations, but I believe we have images of four different frames.
(1) The dark blue bike (image 4 above) is the oldest. It has five luggage rack stays per side:
- The forward luggage rack stay (#1) is pinned to the outside of the seat stay and a strut continues the line from that point on the seat stay to the bottom bracket (pedal hub).
- The next luggage rack stays (#2 & #3) join and terminate on the chain stay.
- The last rack stays (#4 & #5) join and are pinned to the outside of the seat stay extension behind the rear axle.
- It has the blocky rear clamps for the side loader frame.
(2) The light blue frame above is the next version.
- Luggage rack stay #2 has been eliminated.
- Rack stay #3 is welded to the seat stay instead of pinned to the chain stay.
- Rack stay #5 is now welded to the seat stay instead of pinned.
- The rear side loader union is revised to eliminate the clamping block.
(3) The first two images above are the next version (fairly recent). Minor changes.
- The #1 luggage rack stay now terminates in the seat stay and no longer extends through to the bottom bracket (Stoke Monkey friendy).
(4) The current image of the eMundo http://yubaride.com/yubashop/product.php?id_product=28
is the newest incarnation.
- Another luggage rack stay has been removed (originally #4).
- Forward stay #1 has been relocated to the leading edge of the rack and now terminates in the seat tube instead of the seat stay.
I believe there was also some widening of the chain and seat stays in (2) and (4) which is not visible in the images.
I took (1), (2), (3), and (4) to be v2, v3, v3.3, and v4 respectively but I could be wrong about this.... Anyhow, it's interesting to see the evolution and simplification of the design.