The first time we see River is in Silence in the Library, with Ten.
And we know from that episode that obviously she has met the Doctor in his tenth regeneration before, because she recognizes him, even comments how young he looks. Not to mention, she has Ten’s sonic screwdriver.
As far as we have known up until now, she met him off screen that second time, because that particular plot point has been overlooked up until now kind of like Jenny but let’s get into that later.
And at some point, he told River his name.
And as we all know, the 50th anniversary seems to be centered around the Doctor’s name.
But if Ten is coming back in the 50th anniversary, with River, could this be the time she meets him in his tenth regeneration and he gives her his screwdriver? When he tells her his name?