The iPhone 8 is incrementally better than the iPhone 7 in every way except one: battery capacity. A listing on China's version of the FCC, TENAA, shows the batteries are being downgraded in the new devices.

The iPhone 8 will have a 1,821mAh battery, compared to the 1,960mAh battery in the iPhone 7. The iPhone 8 Plus will have a 2,675mAh battery, compared to the iPhone 7 Plus' 2,900mAh battery.

For those how cares about, Tenaa just confirmed #iPhone8 and #iPhone8Plus comes with 2GB and 3GB of RAM, reveals 1821mAh and 2675mAh battery pic.twitter.com/NnIvYkVuAk — Steve H. (@OnLeaks) September 14, 2017

Apple says both phones should last "about the same" as their predecessors. Apple typically does a good job at battery optimization through software, so that could explain the smaller size. Still, it isn't an awesome feeling to know your expensive new phone features a slight downgrade, especially when battery life is crucial to device satisfaction.

Apple's competitors, like Google and Samsung, prioritize larger batteries. The Pixel and Pixel XL from last year have 2,770mAh and 3,450mAh batteries, respectively, while the Galaxy S8 and S8 Plus feature 3,000mAh and 3,500mAh batteries. Apple’s devices last about as long as those devices, though. So even though the company doesn't include the largest batteries available, its phones don't seem to be suffering.