The Tesla Model S 60D owned by Consumer Reports received its automatic emergency braking software update Thursday, but the feature only operates up to 28 mph, according to the digital owner’s manual that was updated at the same time.

That’s far lower than the 90 mph limit for Tesla models outfitted with an AEB system included on models built before Oct. 19, 2016. Tesla told CR on Friday that the lower limit reflects its rollout plan for the new software, and the automaker says higher limits will come later.

CR engineers confirmed the new, 28-mph braking limit in an evaluation Thursday at the nonprofit’s testing facility in Connecticut.

Consumer Reports lowered its ratings on the Model S and Model X on Wednesday because the automaker had not yet enabled the automatic emergency braking safety feature. The company said in October, when it announced its latest hardware update, that it was working on the software. As of this week, some owners had been waiting for up to six months for the promised feature.

Consumer Reports awards bonus points as part of its Overall Score to car models that have forward-collision warning and automatic emergency braking as standard across a vehicle’s model line; models with low-speed AEB systems get a lower bonus than high-speed AEB systems. Once CR confirms that the vast majority of Tesla owners have received this new update, the scores will be revisited. If there are later updates to AEB, the scores can be revisited again.

“We appreciate that Tesla has started to roll out standard automatic emergency braking on these vehicles,” said Jake Fisher, Director of Auto Testing at Consumer Reports.

AEB is an important safety feature: According to the Insurance Institute of Highway Safety, vehicles equipped with forward collision warning and automatic braking see incidents of rear-end collisions reduced by 40 percent, with bodily injury claims cut by 30 percent. CR believes that AEB should be standard on all new vehicles.

In a written statement to CR on Friday, Tesla said it is activating AEB in stages, as it did with vehicles with the original hardware.

“The first step was meeting the IIHS requirements, which are 45 km/h (28 mph),” the company said. “Over the next several weeks, we will increase AEB speed activation until it is the most capable of any vehicle in the world.”

Tesla hasn’t said when all of its owners with new hardware will have the updated software, or when all new models sold will be equipped with AEB. In our experience with earlier updates, it took as long as nine days for our models to receive an over-the-air update. Tesla also did not say when owners can expect to have the braking limit all the way back up to the 90 mph limit that was standard on the previous model.

The AEB system has been a point of contention between Tesla and owners of vehicles built since late October, 2016, when Tesla changed its safety system hardware. AEB had been touted as a standard feature on these newer models, and the automaker had originally said it would be in place by the end of 2016.