Just came across this article here:
https://www.paddleyourownkanoo.com/2...boeing-737max/
United Airlines will end its Boeing 737MAX waiver beginning April 7, meaning that passengers booked to fly on the aircraft will have no choice but to get on the flight or lose their money.
No source was cited.
I checked UA's 737 MAX updates page and it has no updates regarding such April 7th cutoff.
https://www.united.com/ual/en/us/fly...t/737-MAX.html