User blog comment:MrJ17/Putting Together PTD2 Storyline Information!/@comment-5201028-20120708211526

That will be a possibility, all that's known about it though is that you won't be able to trade them into the second game until you get the fourth gym badge. That will allow you to trade anything over from ptd 1 over to two that's level 40 and under.

But in a attempt players made to try to save some their hard work, the suggestion has been brought up to de-level Pokemon and Sam has said to have interest in the idea and I think he'll give people the option to do so since some people mistakenly may have trained their Pokemon to 100 just to have that prestige of having the level cap.

Meanwhile, until the update comes out I'd suggest stocking up as much as possible, especially with shadow poliwags, eevee's, slowpokes. But no so much as into rares such as dogs or mewtwo, etc.

With the de-leveling being a possibility, I wouldn't discriminate against any level you can get. But just to be safe, it also may also be a good idea to save your casino coins for any reason or new updates that ptd 2 may bring.