Steem Basic Income will be operational post-fork as Steem Basic Income. Existing subscriptions will be honored on both chains. New enrollments (post fork) will only affect the chain where the transfer is received.
There may be a short down-time through this weekend as we make the necessary upgrades to support parallel operations on the new chain.
Since this contest was announced pre-fork but resolves post-fork, you may wish to make the reward transactions on both chains (or ask the winner which chain they prefer), even if you plan to only continue operations on one chain.