Pokemon Dungeon Explore of the sky was the lastest version of this series !
Pokemon Dungeon Explore of The Sky is just a extended version of the previous version Pokemon Dungeon Explore of Darkness/Time
In this game you have much more options and different kind of story's playable during the storyline!
Also you have new pokemon added to the game such as : Origin forme Giratina and Sky forme Shaimin
Which are completely new to this game and unobtainable in the previous version Darkness/Time.
If you would like to hear from me if this game is worth the money the shops ask for it... I would say NO. This game is basically the same as the previous version of it! and the only thing that changed was : more story's and new pokemon added to it.
I better recommend you to use a Flashcard and download the game to play it ( Which is illegal but still fun )
Still not convinced to play this game? Just give it a try and see it for yourself " I am talking about downloading it instead of bying it "