So it’s time for, I guess, the most cheerful post of the month where we announce the winners of our monthly challenge.

Our Special Challenge of September was a bit different from earlier ones as it was specifically tailored for developers. We promised to give away a high-end Windows Phone device to one of the developers who started promoting his app or game through AdDuplex cross-promotion network during September. The only conditions where that the app or game must have at least 100 reviews and average rating of 3.5* or more in the Store.

The Special Challenge was even more special because we let the winner to choose his prize from Lumia 1520, Lumia 930 and HTC One (M8).

This time the applauses go to Rune Selvåg for his app Piano Tunes which enable you to listen to beautiful piano tunes and even learn how to play them. Rune selected Nokia Lumia 930 as his prize. Congratulations!

Winners of Publish Your App Competition.

And of course two more Windows Phone devices to two random developers that started using AdDuplex cross-promotion during September.

So Adan Garcia and his app GameBoy Cam gets Prestigio 8400 DUO (or $1000 AdDuplex advertising credit) and Emanuel Takano and his game Stickman World gets Prestigio 8500 DUO (or $1000 AdDuplex advertising credit).

Congratulations to both of you!

And check out what Windows Phone devices we have prepared this month.