The F1 Commission has voted through last-minute changes to the 2019 Formula 1 aerodynamic package to aid overtaking, despite opposition from several teams.
A proposal to change front wing endplates to help cars follow each other, along with a bigger rear wing flap and therefore a stronger DRS effect, has been passed.
An extra package involving bargeboards was not agreed to.
The vote took place on April 30, the last day when technical regulation changes for next season can be passed without unanimity being required.
Under F1 Commission rules a proposal can be pushed through with support from as few of four of the 10 teams if everyone else - the FIA, F1, and sponsor and promoter representatives - are behind it.
Even so, several team bosses suggested in Baku there would not be enough support to vote it through, with only Williams publicly in favour.
Although there has been no official confirmation it is believed that up to six teams were still opposed to the plans.
Sources suggest that Ferrari, Red Bull, Renault, McLaren, Toro Rosso and Haas voted no, and that Williams was joined by Mercedes, Force India and Sauber in voting yes.
The F1 Commission vote still needs to get approved by the FIA World Motor Sport Council to be put into the 2019 rules.
While this should in theory be a formality, it is unclear if Ferrari could try to use its veto over technical rule changes to block the tweaks.
Ferrari would have to prove the changes would have a negative effect on it - for instance because they would be too costly - rather than the team just not being in favour of them.
The wing changes proposal was a direct response to the lack of overtaking in the Australian Grand Prix, which prompted the FIA and Liberty to consider possible improvements for 2019.
They were able to draw on some of the research already conducted for the 2021 rules package.
When a meeting of team technical bosses in Bahrain failed to reach a resolution, it was agreed that teams would conduct extra CFD research of their own to try to make progress before the April 30 deadline.
The FIA used that research to create a report that informed Monday's vote.
The rejected extra bargeboard changes were added relatively late, and were not part of the teams' CFD research.
Williams chief technical officer Paddy Lowe has been the most vocal supporter of the changes, saying "this is the time that F1 should act and act decisively for the good for the show" in Baku last weekend.
Other teams preferred to avoid piecemeal changes before the 2021 overhaul.
"In my opinion F1 is good enough for the next two years," Renault F1 boss Cyril Abiteboul told Autosport.
"It can be slightly improved with twists to the sporting regulations, and we will make proposals on ways to make the show better, but we should not distract ourselves from the main objective, which is 2021 overall."