Xiaomi Mix Flip and Mix Fold 4 hands-on review

Xiaomi Mix Flip and Mix Fold 4 : Latest About Xiaomi's Foldables  

Xiaomi's first flip phone comes on the heels of the the Galaxy Z Flip 6 and the Razr Plus 2024. And just like its competitors, it has a large cover screen. Xiaomi announced the Mix Flip at an annual event in Beijing alongside the skinny book-style Mix Fold 4. Both phones are reserved for a release in Xiaomi's native China for now, but Xiaomi didn't share pricing information. Unlike the Flip, the Mix Fold is already in its fourth generation, which means it's a rather mature product. Xiaomi has further reduced the thickness and weight here and we are finally reaching a point where foldables are not that different size-wise from a regular "slab-style" phone. The Mix Fold 4 measures just 9.47mm when folded and tips the scale at 226 grams. All the while, it houses a 5,100 mAh battery. It really feels like using a regular phone when folded, and the slightly curved edges of the cover display also help. Xiaomi's first flip phone has a cover screen that's so big you might not actually have to flip it. The Xiaomi Mix Fold 4 is the company's latest book-style foldable phone. 

Like Samsung and Motorola's flip phones, the Mix Flip has a large outer screen, measuring 4 inches. Xiaomi says you'll be able to meet most of your daily needs without needing to flip open the device. The Mix Flip's outer screen partition design, along with dynamic widgets, gives you quick access to the cameras. You can also check the time, weather and other notifications. Xiaomi says the outer display also offers an AI experience, which adapts to your habits and provides a personalized experience. When unfolded, the Mix Fold 4 measures just 4.59mm in thickness. That's razor-thin. We find the power button/fingerprint reader particularly thin and kind of uncomfortable to use. The hinge on the Fold 4 feels super solid, though, much more so than that on the Flip. It offers a smooth linear motion, allowing the phone to stay open at any angle. There is a satisfying and reassuring snap when you close it fully. Xiaomi is calling the hinge a "proprietary hinge 2.0". It is made with 1800MPa high-strength steel and T800H high-strength carbon fibre. Just like on the Flip, there is practically no gap between the two halves of the phone when the phone is closed.    

The last two years have seen flip phones undergo a design transformation, with much of the change happening on the front screen. This may have been kicked off by Chinese phone-maker Oppo, which shook up the cover design of flip phones in late 2022 by introducing a vertically oriented cover screen to its first-ever flip phone, the Find N2 Flip. The 2023 Motorola Razr Plus was then outfitted with a larger 3.6-inch cover screen. Samsung later followed suit, expanding the Galaxy Z Flip 5's outer display, a design it retained with 2024's Galaxy Z Flip 6. The back of the Mix Fold 4 is made of glass, and just like the Flip, it feels very smooth and soft, almost velvety to the touch and doesn't attract too many fingerprints. Unfortunately, it's the same finish that's quite easy to scratch, and is super slippery to booth. On a more positive note, the Mix Fold 4 has IPX8 ingress protection, a first for a Xiaomi foldable. 

The Xiaomi Mix Flip has a giant cover screen. The reason behind the growing size of these outer screens was to help create a more useful and interactive cover screen compared to the ones of years past. Previously outer displays on flip phones such as the Galaxy Z Flip 4 were useful for cursory checks, but not much else. The Mix Flip may also have one of the brightest outer screens around, with a peak brightness of 3,000 nits -- the same level as the Razr Plus 2024. By comparison, the Z Flip 6 has 2,600 nits. On the cover screen, you can see a pair of Leica-branded cameras in a vertical layout. They consist of a 50-megapixel main camera and a 50-megapixel "floating" telephoto lens, which should dynamically adjust its internal elements to optimize image quality across various shooting distances. (A regular telephoto lens maintains a fixed focal length.) Xiaomi says the cameras offer various photography modes, including hover mode, to help take stable shots without a tripod. 

Within its chassis, the Mix Flip runs on Qualcomm's top-of-the-line Snapdragon 8 Gen 3 chipset and has a 4,780-mAh battery with support for 67-watt wired charging. Unlike the Z Flip 6 and Razr Plus 2024, the Mix Flip lacks an official IP rating for water- and dust-resistance. You can get the Mix Fold 4 in Black, White, Blue or Xiaomi Composite fibre edition. Xiaomi says that its new composite fibre 2.0 has 42% more tensile strength, 25% improved rigidity and 15% improved impact resistance. While the body of the phone is fairly thin, it has a really huge camera hump to accommodate what may well be the most capable camera setup on a foldable (pending confirmation in a full review). It sticks out quite a bit, making the phone unstable on a flat surface and noticeably top-heavy. The glass around the camera hump is patterned, and you can feel it with your finger.

The outside display of the Mix Fold 4 is a nice and spacious 6.56-inch unit, while the inner display measure 7.98 inches. Xiaomi made these two panels remarkably similar in terms of performance. Both offer a pixel density of around 418 ppi and a dynamic refresh rate between 1Hz and 120Hz. Both can also do 1,700 nits of whole display brightness and up to 3,000 nits of peak brightness and have DC dimming. This makes content appear very similar regardless of which display you choose. The internal display also has UTG protection. Unfortunately, the situation with the crease isn't great. It is both visible and noticeable with a finger. The Mix Fold 4 has a powerful set of cameras at its disposal. As we mentioned, the camera island sticks out quite a bit on the phone's rear. The rear camera island houses a total of four cameras. There is a 50MP main camera, a regular 50MP telephoto, and a 10MP dedicated 5x periscope-style shooter. The regular 2x telephoto has a floating-style lens and can also be used for macro shots. On top of that, there is also a 12MP ultrawide cam. Leica is using a next-generation Leica Summilux lens for the main camera. It employs a 1G + 6P lens structure with professional-grade optical materials for high transmittance and next-level high-stability coating. This is a high-order polynomial lens.

Xiaomi also debuted its next-gen Mix Fold 4, which is 9.47mm when folded close, making it one of the thinnest book-style foldable phones sold commercially, second only to the Honor Magic V3. The Mix Fold 4 has a 6.56-inch outer screen that opens up like a book to reveal a 7.98-inch inner screen. Both screens have a refresh rate of up to 120Hz. Xiaomi credits the Mix Fold 4's "all-carbon architecture" for reducing its weight and thickness. It also reduced the hinge's total volume. According to the company, the hinge floating plate, screen backing plate and middle plate battery compartment are all precision-molded from carbon-fibre materials. Carbon fibre is a strong and lightweight material, but it comes at a cost and has been reported to suffer from brittleness. 

The announcements wouldn't be complete, especially in 2024, without mention of AI features. Xiaomi said the Mix Flip can offer AI-driven language translations in real time even when you're not connected to the internet. Those translations show up on both the inner and outer displays. Xiaomi introduced a so-called Travel Assistant feature, which Xiaomi says provides reminders of travel information during flights and train journeys as well as a feature that helps with text generation. Xiaomi says the Mix Fold 4 has been tested to withstand 500,000 folds. It has an IPX8 for water resistance, which means it can survive submersion in water, but it cannot protect against dust ingress. Despite the thinner design, Xiaomi says it's expanded the Mix Fold 4's battery capacity by 260 mAh, bringing the total capacity to 5,100 mAh. It has a silicon carbon battery instead of the now-traditional lithium ion ones, following in the footsteps of Honor's Magic V2. The use of silicon-carbon batteries in mobile phones is an emerging trend that's drawn attention due to its potential advantages over lithium-ion batteries. Those benefits include a lower environmental impact and reduced risk of overheating. The long-term reliability of silicon carbon batteries is still being researched, and adoption in the smartphone industry is still in its early stages.