Augur announced it’s deployment on the Ethereum main network on July 9th, 2018. With that they will also conduct a migration of the REP token balances, so that the new REP token exists inside the Augur genesis universe. The deployment and REP migration will begin on July 9th, 2018 at 11:01AM PDT. After that the current REP token will be frozen indefinitely and the transfers will not be possible anymore. In the hours following, they will be minting all REP token holders an equivalent amount of REP on the new REP contract, which will be the REP contract going forward.
GateHub will freeze REP transactions one hour before the migration starts (10:00AM PDT) and the migration shouldn't take more than a few hours. As a user there is nothing you have to do and we will update you on the progress.
You can read their official press release for more details.
UPDATE: Augur contract deployment and REP token migration has been successfully completed. REP will be processed normally from now on.