Apple explained the same situations for customers in its official apology on its website, which also announced the company's new battery replacement program. They are also dealing with a bunch of class-action lawsuits from disgruntled customers, so we can imagine that the whole "batterygate" scandal probably won't be dying down anytime soon.
In the update, Apple included maximum battery capacity measurement compared to when it was new, and peak performance capability to know if you're getting the most out of the battery.
If the battery's health is severely degraded, iOS 11.3 will add another message below which recommends that you replace your battery in order to restore full performance. The Battery Health feature will allow users to see if their iPhone is impacted by performance throttling.
Apple also links to a support document providing more information about the iPhone battery and performance. The giant has released this update to the developers which brings new features to your phone. This will give you a status of battery's maximum capacity and whether or not your device is running at peak performance.
Apple's tech genius advice is to turn their phones off and turn them on again. It's notable in that it lets us have a first look of Apple's proposed solution to how we can monitor our Battery Health and control what Apple is calling the "Peak Performance Capability" of our iPhones. If it does kick in, users have the option of turning it off, at their own risk. But that's not all, this section will also show you whether or not you are being throttled or not.
While a generous interpretation might view Apple's hardware updates as standard in-line improvements to new devices, another view is that this is effectively an admission of a chip or hardware design defect affecting certain iPhones, the depth of which was initially obscured.
Performance management is off by default resulting in your phone being prone to sudden shutdowns.
Last week, Apple came under scrutiny again when the US Justice Dept. and SEC started the investigation over performance throttling in older iPhones. Apple's battery health feature will display this message: "Your battery is now supporting normal peak performance". More about service options... According to Apple this will be due to "an improperly installed battery or an unknown battery part".
If you've purchased your iPhone overseas such in China, Hong Kong, Japan, Macao or the U.S. and was produced between September 2016 and February 2018 then your device could potentially be affected. However, the most significant features that would have radically changed the iOS experience are nearly certainly going to be delayed so engineers can focus more on the reliability side of the OS. You may get more augmented reality features than you'll ever use, more parental control settings and more health tracking features.