I went to Winx Club Episodios, and saw that the Brazilian Winx Facebook have posted this:
I went and translate(please credit, it took me very long to translate it!)and here's what it said:
Can't wait!Before the debut of the series, the Nickelodean will show a four-part special that tells the story of the Winx fairies. PREMIERE: Wednesday, October 26 at 16:30.