On April 10, a new Presidential Proclamation was issued which amended P.P. 9645 of September 24, 2017.
The new P.P. removed the visa restrictions imposed on nationals of Chad by the previous September 2017 proclamation. This change is effective at 12:01a.m. EST on April 13, 2018.
All other visa restrictions outlined in P.P. 9645 remain in effect.
See more here.