CPB has been working to make a transition to all electronic filing of protests to ACT, the Automated Commercial Environment. A series of notices lays out some of the guidelines and deadlines, and on August 8th, CBP announced the addition of a one-day grace period; CBP stated that it will accept protests filed in the ACE Portal past the required due date. Beginning on August 27th, all Protests must be filed in the ACE Portal. The transition from ACS to ACE will occur on August 29th, 2016, and since the ACS will be down on August 28th for the cutover, CBP will allow any protest due on August 28th to be filed in the ACE Portal on August 29th.
A complete summary of the transition dates and necessary steps for using the new system is available at CBP at: https://www.cbp.gov/trade/automated/news/protest