So this year, what changed with Ahri?

Okay, so basicly, last time i actually played lol was like, last september. I come back and my main is different. Normaly, i'd never start with mana stuff. I'd always be something like ring/mr/boots and that's how i'd build it. Possibly in rare occasions I'd take a mana booster, but thats only very rare. No matter what, i'd always slash something like 24/2 in most games. Now, i'm getting 1/8 and my mana drainnns just way too much. I saw a lot of changes in other champions too, which sucks because now I don't know how My opponents are any more. But anyways, i'm only here for my precious . Could someone please tell me what's different with her? I rlly love my old build and I rlly don't want to get rid of it! but for now I guess i'll try all the new items. Ty!