Yesterday i tried a game as 
in hopes to see /try out her rework, but she was still the old copy. Is it because it hasn't been released yet, or just something wrong with my game?
Also, 2 additions to this post:
When are the new batch of skins being released? I can't wait to buy Arbiter Vel'Koz :)
And 2: look at the pic.
InvalidGuest3 votesLet me explain something:
So The day before a new patch is released, a new PBE cycle starts. That new initial PBE update usual has the new skins, new champions, etc.
The tristana update and arbiter vel'koz etc. is still being tested on the PBE so it isn't even on this current live server patch.
They will be added next update which is around 2 weekish from now.
The 5.1 patch only had the new skins "Challenger Ahri" and "El Braum"
Also aatrox got a really awesome skin a few months ago
The Chin1 votesnone of those things have been released yet
and why are you waiting for an aatrox skin, they have mecha aatrox!!!
FreshMeat7071 votesMecha Aatrox is really awesome, i agree, but i have a very small amount of money and RP left and i would rather wait and see i he gets a new skin than to use up all my RP
The Red Warden1 votesDon't count on it usually it is 2 years between each skin a champion gets, and he may be planned for a kit rework meaning that it is actually 3 years. Mecha Aatrox is his best skin at the present so buy that if you want a skin for him.
Riotmoonstones1 votesTristana's updates are still in testing on the PBE, and won't be on your client or anyone else's this patch. :]
As for Vel'Koz, he won't be released this patch, as he too, is still in PBE testing!
FreshMeat7071 votesI also wanted to imply a long time ago that if The Red Warden was being serious, is 
getting a kit rework!?!?!? :D
Jeddy0171 votes just got the mecha skin last summer,at least wait 2 years or so for another skin.