Hearthpwn

I have a question about the standard changes and rotations, like Ragnaros the Firelord rotating out.

When are these changes happening? Is this soon, or with the upcoming new expansion? I'm not sure where the source for the data is, but I'm getting a bit confused. Generally a new card set would rotate an old one out, but in this case there are also some nerfs and changes happening before that, for example Spirit Claws costing more mana. All I know is what I hear. 

Thanks!

I believe the cards rotating out of classic will happen with expansion, and the nerfs are happening any day now. (from what I understand anyway)

Blizzard said "late February" but well, it's the last day of February and it still didn't happen. Maybe they think February has 30 days?

EDIT: I mean the nerfs. The rotation to wild of Sylvanas etc is with Un'Goro.

The nerfs will go with the tonight maintenance

Thank you all for responses. Appreciate it.

http://www.hearthpwn.com/forums/hearthstone-general/general-discussion/186554-when-are-the-nerfs-gonna-happen

http://www.hearthpwn.com/forums/hearthstone-general/standard-format/186243-when-is-the-rotation