There is only one chain, they need to resync. There would only be a fork if the chain was changed (which there were no changes to), please read up on how blockchains function. The issue with the update just underscores what we are trying to fix, slapping good working code on the testnet and working properly for a week then launching live on the network with an unidentifiable issue is exactly the type of problem we are fixing. We will just push all these updates into the java wallet and stop trying to put makeup on the pig. The btc pig is very cute but its fat, slow, unstable and dirty. And until someone cleans it up its just going to be bad code.