Madonna's manager Guy Oseary reprised his tweets after a few weeks hiding, and talked again to her number one fan.

@guyoseary Long time no Tweet! Been well?
@perezhilton hello. I've been hiding.. Im in NY.. its the second day of Madonna tour rehearsals. will we see you in europe this summer? -guy
@guyoseary I'm gonna try. Europe is so far! But I do love Madonna lots and lots. She's doing Who's That Girl is the new song, right? ;-)
@perezhilton she's not doing "Who's That Girl"...

The news about Madonna reportedly working on a reworked version of her 1987 hit to be included in the 2009 leg of her Sticky & Sweet Tour came in mid-April straight from her official website, where a new members only section focuses on non official nor confirmed whisperings related to her artistic career.
Actually, Who's That Girl was never part of the revised setlist, and now you heard it from Guy's mouth, too.
In more tweets, Guy confirms negotiations for bringing the show to Istanbul, explaining that the timing didn't work because they are in the area at the same time as Ramadan.
He also told another fan that Madonna tells him daily that she can't wait to go back to play in Latin America again. "She loves it there," he says.

Source: MadonnaTribe