General Motors and United Auto Workers have reached a tentative agreement on a new contract, , putting in motion a possible end to the strike that began one month ago to the day. The agreement still needs approval from the union council and ratification by union members.

Details of the agreement are not immediately available, but we will update this post as they come out. The strike, which began at 11:59 p.m. on Sept. 15, is the longest at GM since 1970. Workers, for now, will remain on strike until at least Thursday, when the UAW GM National Council will meet and vote on whether to recommend ratification of the agreement to members. The UAW could also decide to go back to work then, though if they wait for full ratification, the strike could go on for several more days.

Ratification of the agreement among membership—assuming the council recommends as much—is no sure thing. As :

If they vote the first proposal down—as did Fiat Chrysler workers in 2015—company and union negotiators will have to return to the bargaining table to hash out a deal they believe the members will support.

A potential wild card for union leaders is roughly 42% of GM’s factory workers have never seen an industry downturn and might be a harder sell on any deal that doesn’t fully meet all their demands, according to people close to the negotiations.

“Things are different now,” Arthur Schwartz, a consultant and former GM labor-relations executive said. “You’ve got brand-new leadership, a Justice Department investigation and this is already the longest strike we have seen in a long time.”

: A reminder of GM’s last proposal to the UAW before this agreement was announced, :

GM’s most recent offer to the union included plans to invest $7.7 billion in U.S. plants, a person familiar with the negotiations told Automotive News. Reuters reported GM’s proposal included guarantees to hire temporary workers to full-time positions after logging three years with the company.

GM had also proposed 3 percent pay raises in the second and fourth year of the four-year pact, and 3 percent and 4 percent lump sum payments in the first and fourth year, respectively, Reuters reported. GM would reportedly offer full-time workers a $9,000 ratification bonus and temporary workers a $3,000 bonus, according to Reuters.

: The UAW says that it won’t release details of the tentative agreement until it tells its leaders to hear them first.

GM officials said in a statement, “We can confirm the UAW’s statement regarding a proposed tentative agreement. Additional details will be provided at the appropriate time.”