I'm sure this has been answered before, but I looked through forums on both the old and new versions and couldn't find a direct answer.
I bought the old version a couple years ago for a premium since it was OOP/HTF, and therefor out of principle want to keep it. Can I download the new rules and play those with the old version?
Some of the Loki/Odin cards are different so you'd have to substitute the rules of 2 of the cards, but other than that I think you could play the new version's rules with the old game. I don't know if there are more or less cards in the new version, but I do know the path is longer so there might not be enough cards.
*Rearrange your auxiliary card stack
Place 2 additional landscape cards at the end of the flight path.
*Place the Odin marker on an unoccupied landscape space.
Swap 2 unoccupied landscape cards.
*Draw 2 extra cards
Draw an extra flight card and put it alongside one of the flight path sides. The extra card adds 2 more spaces to make the flight path longer.
Swap any 2 land cards without rotating them.
*Slide one land card so that one flight path changes and the other gets shorter. The section which is outside the flight paths is ignored.
*denotes differences because of no Odin marker or auxiliary stack