Newark teachers are due for a $2.5 million windfall this year, and hundreds more can expect hefty raises in the future, thanks to a new agreement between the district and the city teachers union.

The agreement stems from an arbitrator’s finding that the district violated several provisions of the 2012 teachers contract, which was touted at the time as a national model. In the document inked this month, the district agreed to make several payments demanded by the arbitrator and to negotiate pay raises for teachers who earn advanced degrees — ending a feature of the 2012 contract that replaced such raises with one-time bonuses for teachers who completed a controversial training program.

While the terms of the raises must still be negotiated, they could prove costly to the district. The union estimates that between 200 and 300 teachers who earned degrees in recent years are eligible for retroactive raises which, in the past, ranged from $2,500 to $4,000 depending on the type of degree.

The payments highlight the bind that Newark’s new superintendent, Roger León, finds himself in as he tries to enact his own policies while at the same time confronting costly unresolved matters left by the previous two superintendents — all without the massive influx of private funding that bankrolled many of his predecessors’ efforts.

In fact, the contract settlements may be the least of León’s worries.

At a school-board meeting this month, León said a legal matter triggered by the previous administration has temporarily blocked him from hiring attendance counselors — a key component of his plan to combat the district’s severe absenteeism problem. And, without giving specifics, he cited a fine related to employee health insurance that the district incurred in 2015 but never paid.

The current price tag: At least $48 million, León told the board.

“P.S., I began on July 1,” he quipped — a pointed reminder that his financial headaches, for now, are largely inherited.

The agreement between León and the Newark Teachers Union includes $1.7 million for various groups of teachers who were shortchanged under the terms of the 2012 contract, according to the 2017 arbitration decision. (Former Superintendent Christopher Cerf appealed the decision, but a superior-court judge recently upheld it.)

It also includes $816,000 in raises for the district’s highest-paid teachers, which stemmed from a clause in last year’s contract enabling the new administration to renegotiate raises. León agreed to increase salaries by the maximum amount allowed by the contract — from 2.95 to 3.25 percent.

The most far-reaching — and expensive — part of the agreement is likely to be the pay hike for teachers who earn postgraduate degrees.

The 2012 contract did away with the district’s traditional salary system, which put teachers with master’s or doctorate degrees on a higher pay scale. Instead, the contract allowed for teachers who completed a district-approved graduate program to earn a one-time bonus of up to $20,000.

Then-Superintendent Cami Anderson and Cerf, who at the time was state education commissioner, had two goals in pushing for the change. One was to reduce costs. Calling the graduate-degree raises “prohibitively expensive,” Anderson said during an arbitration hearing that the district expected to pay for the one-time awards with private money that wealthy donors, including Facebook founder Mark Zuckerberg, had provided to finance an overhaul of the district.

The other objective was to spur changes in teacher-training programs. District officials did not believe that most universities had sufficiently revamped their programs to prepare teachers for the state’s new, more rigorous “Common Core” learning standards that teachers now were expected to help students meet. The idea was to award bonuses only to teachers who attended Common Core-aligned programs, which would pressure colleges and universities to update their approach.

“This was all to incentivize the higher-ed community to do more, better, faster,” Anderson said in her testimony, “and also about rewarding teachers who were bettering themselves — not on the old way of teaching, but on the way that the new Common Core would demand.”

The contract called for a committee with representatives from the city’s teachers union and higher-education to recommend criteria for the district to use in approving programs. However, the district never convened that committee, according to the arbitrator’s findings.

Instead, more than two years after the contract was signed, the district on its own approved a single program: the Relay Graduate School of Education, a relatively new and controversial institution with close ties to the charter-school sector. Only teachers who completed that program could earn the $20,000 bonus.

The arbitrator, James Mastriani, said last year that the district must actually convene the selection committee and determine which degrees will merit a bonus payment. Teachers who previously earned degrees from approved programs would then be eligible for the applicable bonuses.

However, the deal between León and the union abolishes that bonus program and restores a version of the old system, where teachers with graduate degrees from any institution received higher pay.

The value of their degrees going forward will be determined next year, when the two sides negotiate a new contract to replace the current one, which expires on June 30. Crucially for the union, the salary increases will also grow members’ pensions — a benefit not offered by the one-time bonuses.

“Instead of continuing to try and make an unwieldy, tainted system work,” Newark Teachers Union President John Abeigon wrote Monday in an email to his members, “we got the district to agree in writing to work with us on putting the original time-tested system back in place during our next contract negotiations.”

The agreement adds that any employee who earned a graduate degree since the start of the 2012 contract will be eligible for a retroactive salary increase. Union officials pointed out that it does not put any restrictions on those degrees — meaning hundreds of teachers could eventually get checks with sizable back payments.

In an interview Tuesday, León insisted that this was not a blanket pay hike. Instead, he said he would push during negotiations to give raises only to employees who earned advanced degrees that are relevant to their jobs or teaching assignments.

“We will review every single one of those people’s degrees,” he said.

It will not be clear until after next year’s contract negotiations how much the raises will cost. It’s possible they could eventually dwarf the price of the $20,000 bonuses if teachers who receive the salary bumps remain in the district for many years.

León said he did not expect that. He added that, with the private money that paid for many elements of the 2012 contract now spent, it would be hard for the district today to afford the bonuses.

“Where am I going to get that money from?” he said.