Apple has officially responded to a request for more information on the iPhone battery degradation scandal, telling the US Senate that users weren’t informed at first in the iOS update implementing the throttling about the performance impact on their devices.

In a letter sent to Senate lawmakers and released on Tuesday, Apple says the iOS update supposed to deal with unexpected shutdowns of iPhones with worn-out batteries was introduced in January 2017. This update was supposed to reduce the performance of devices with degraded batteries.

But Apple only included the power management changes in the iOS release notes a month later in February when most iPhone users were already running the said OS version. It’s a well-known thing that adoption of the latest iOS versions increases fast after the official launch, but it’s not known how many iPhone users installed iOS 10.2.1 in the timeframe between January and February 2017.

iOS release notes updated one month after launch

“We first delivered this power management feature to iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, and iPhone SE as part of iOS 10.2.1, in January 2017,” Apple VP of public policy Cynthia Hogan explained in the letter sent to the Senate.

“Once we verified that the feature was effective in avoiding unexpected shutdowns, we updated the iOS 10.2.1 ReadMe notes in February, 2017. Specifically, the iOS 10.2.1 ReadMe notes said that this update ‘also improves power management during peak workloads to avoid unexpected shutdowns on iPhone.”

Interestingly, CEO Tim Cook said in a recent interview that iPhone users actually knew from the very beginning what effects the update would have on devices with degraded batteries.

“When we did put [the software update] out, we did say what it was, but I don’t think a lot of people were paying attention,” Tim Cook said in the statement.

These contradictory statements certainly don’t do any good to Apple’s image, especially at a time when the company is being investigated and sued across the world for slowing down iPhones without telling users.