Neos will be upgrading their blockchain to a new blockchain which is improved and faster than the existing one.
All Neos users will retain the balance of their Neos addresses, which will be migrated to the new blockchain.
Users' Neos Bittrex exchange balance totals will reflect the same total that they had prior to the swap in a 1:1 manner. Once the swap is complete, all tokens from the old blockchain will no longer be supported or traded on Bittrex.
Bittrex will re-enable the Neos tokens (NEOS) wallet when we and the Neos team agree that the migration is satisfactory.
Note: Bittrex will be closing our NEOS wallet on 7/5/2018 and may stop trading the token to take accurate snapshots of balances. If any NEOS deposits you had sent to Bittrex are not settled (e.g. marked as pending) by 6:00 PM PT, on 7/5/2018 (1:00 AM on 7/6/2018 UTC), you may not be credited with NEOS.
We would like to thank the Neos team for working closely with us.
Further information: Reddit thread announcement - r/NeosCoin