I just spoke with Richie at Bittrex. There were a bit over 3 million coins on the exchange, so we sent him the exact amount to do the swap. If you had your coins on Bittrex, you do not have to do a thing, they are on the correct blockchain now. Please make absolutely sure that you download the new wallet (link below) because you cannot send these x13 coins to your old x11 wallets.
Please make sure that you move your old Roxcoin wallet directory in %appdata% as the new one will try to claim the same directory and the wallet will not start. If you did not have coins on Bittrex you MUST keep your old wallet.dat and e-mail it to us along with your new ROX wallet address so we can manually exchange coins for you.
Source:
https://github.com/Roxcoin/roxcointorWindows wallet:
https://mega.co.nz/#!NBAAUIjY!JZcfbZs8zlFqzZXyjs6CgVSiE6WXZI7IMjOQFTwolek
Email:
roxcoin@hotmail.com