Lei Jun has confirmed that the Xiaomi Mi MIX 2S will get upgraded to Mi 8's camera quality. Xiaomi's CEO said that the company will push Mi 8 camera firmware to its Mi MIX 2S flagship in the near future, as both devices ship with the same rear-facing camera setup, but the company did improve the camera on the Mi 8 further, since the Mi 8 launched quite recently, while the Mi MIX 2S arrived back in April.
DxOMark gave the Mi MIX 2S 97 overall camera rating, while it managed to score 101 in the still shots department. The Xiaomi Mi 8, on the other hand, managed to grab a 99 overall rating, and 105 in the still shots department. Now, to be more exact, both the Mi MIX 2S and Mi 8 sports two 12-megapixel cameras on their backs, the main shooter sports Sony's IMX363 sensor with an f/1.8 aperture lens, 4-axis OIS, and a 1.4um pixel size, while the other camera boasts Samsung's S5K3M3 sensor, an f/2.4 aperture lens, 1.0um pixel size, and a 2x optical zoom, so it's basically a telephoto lens. It is worth noting that the front-facing camera setups are not the same, though, as the Mi MIX 2S sports a 5-megapixel camera, while the Mi 8 comes with a 20-megapixel one. The Xiaomi Mi MIX 2S and Mi 8 are both the company's flagship smartphones at the moment, the Mi MIX 2S, Mi 8, and Mi 8 Explorer Edition are all fueled by the same SoC, and ship with high-end specs, while none of them are small, not by any means. So, it's all a matter of preference, as the Mi MIX 2S is made out of ceramic and it does not sport a display notch, while the Mi 8 is made out of glass and does sport a display notch, while it is a bit larger than the Mi MIX 2S.
Qualcomm's Snapdragon 845 64-bit octa-core processor fuels both the Mi MIX 2S and Mi 8, both phones come in both 6GB and 8GB RAM variants (Mi 8 Explorer Edition features 8GB of RAM). Both devices sport a rear-facing fingerprint scanner (Mi 8 Explorer Edition comes with an in-display unit), while Android Oreo comes pre-installed on both devices, though the Mi 8 comes with Android 8.1 Oreo, while the Mi MIX 2S sports Android 8.0 Oreo. MIUI 9.5 is included on top of Android Oreo on the Mi MIX 2S and Mi 8, though MIUI 10 is coming soon.