The top officials overseeing Newark’s controversial school-enrollment system have resigned just weeks after the school board blocked the new superintendent from ousting them.

Their departure creates new uncertainty for Newark Enrolls, one of the few enrollment systems in the country that allows families to apply to district and charter schools through a single online portal. Proponents say the centralized system simplifies the application process for families and gives them more options, while critics say it undermines traditional neighborhood schools while boosting charter-school enrollment.

Gabrielle Ramos-Solomon, chief of the Newark Public Schools division that includes enrollment, and Kate Fletcher, executive director of the enrollment office, both departed on Friday. The district did not provide information about why they left or who — if anyone — will replace them, and neither of the two could be reached for comment.

Their departure comes after Superintendent Roger León, who took over on July 1, included them among 31 officials and administrators who were given the option to resign or face being fired. Days later, the school board approved all but nine of the dismissals; Ramos-Solomon and Fletcher were among those spared.

Both officials were hired in 2013 shortly before former Superintendent Cami Anderson unveiled the enrollment system, then called One Newark, as part of a sweeping overhaul that also included closing some schools. Parents were outraged by the closures and the system’s glitchy rollout, which left some students without school placements and separated other students from their siblings.

In recent years, Ramos-Solomon has overseen improvements to the system, including tweaking the computer algorithm that matches students with schools to give a greater boost to families who live near their chosen schools. While district data shows that most students are matched with one of their top choices, critics remain wary of the system and some — including some board members — call for it to be dismantled.

León, a veteran Newark educator who was expected by some observers to oppose Newark Enrolls, said in a private meeting with charter-school leaders that he intends to keep the process in place. But he will have to win over the board, whose members have asked the district skeptical questions about the system in recent months, such as why some students are reportedly matched with charter schools they didn’t apply to. (The district says that does not happen.)

Board member Tave Padilla said he was not aware that Ramos-Solomon or Fletcher had resigned, and did not know whether replacements had been lined up. He added that the board had not discussed the fate of Newark Enrolls since a meeting in June where Ramos-Solomon provided information about the system, nor has the full board discussed the matter with León.

“The district now does have the option to keep what we have in place, modify it, or do away with it,” he said. “Whether we choose to do that or not, I don’t know.”