[REVIEW] Xiaomi MIX Fold 4: A top-tier device that turns heads and never makes it to the global market

Xiaomi sticks to modern trends and is also involved in making foldable devices. Recently, we published an exclusive review of their debut “flip” model, Xiaomi MIX Flip, which pleasantly surprised us in practically every way.

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We’re the only ones in Slovakia and the Czech Republic who have access to another flexible model from this year for review: Xiaomi MIX Fold 4. Looking at the specification list, it already looks breathtaking. It wows from the very first contact. But is it just as great in real life? Find out in our upcoming review of the Xiaomi MIX Fold 4.

Where to buy the Xiaomi MIX Fold 4?

Together with the Xiaomi MIX Flip, we ordered the Xiaomi MIX Fold 4 from our partner seller TradingShenzhen. Delivery took just 10 days. Shipping Global Priority will cost you a few euros, and you’ll be glad you won’t have to pay any additional customs duties or VAT.

Even the fact that it’s a Chinese version didn’t put us off—it’s very unlikely to ever reach the global market. The device fully supports LTE band B20 as well as the latest 5G networks. That means you can use it without any issues with our Slovak, or European, mobile operators.

The device comes with a Chinese ROM installed. That means the software is localized in Chinese or English. When we turned the phone on for the first time, we were taken straight into the system instead of the usual screen used for initial setup.

The reason is that the seller turned on the phone before shipping and installed Google Play Services along with the actual Play Store, which we rely on for Android devices in Europe. You can choose the blue, white, or black color variant, and there’s also a special “fiber” black color. The available memory versions are 12 GB + 256 GB (the one we tested), 16 GB + 512 GB, or 16 GB + 1024 GB.

Technical specifications of Xiaomi MIX Flip

In the box

The box in which you’ll receive the Xiaomi Mix Fold 4 is bigger due to the smartphone’s unconventional design. Compared to other packages, it’s wider and thinner. Inside, you’ll find the open smartphone, wrapped in film. Below, there’s a 67 W charging adapter with a Chinese plug and a USB-A to USB-C charging/data cable.

The seller will also include a European adapter plug. The accessories come in white. There’s also a case made of two parts. The first one protects the back, and the second then protects the front of the foldable smartphone. Before you put the covers on, you should peel off the protective strips that shield the delicate adhesive. This prevents the covers from coming loose from the smartphone’s thin edges.

Design and build

Xiaomi MIX Fold 4 is definitely among the thinnest foldable smartphones on the market. When it’s open, the device’s sides are just 4.59 mm. When the phone is folded, it feels like a regular smartphone. You get a thickness of 9.47 mm, which is only slightly more than the standard thickness of today’s typical mobile phone.

The competing Honor Magic V3 is even a little thinner—when open it’s 4.4 mm, and 9.2 mm when closed. Its weight is 226 g / 228 g depending on the color. A nice safeguard in case of an unfortunate accident is the water-resistance certification IPX8. Xiaomi MIX Fold 4 should stay at a depth of 1.5 meters for 30 minutes.

In your hand, it feels incredibly premium and futuristic. The sides are metallic and glossy. The back is matte and, in our case, comes in a nice blue color with a subtle, discreet sparkling effect. The top part of the back houses a fairly large camera module. It’s all made of glass, and we were worried it would pick up fingerprints.

But that’s not true, because the areas outside the lens themselves have a fine texture that prevents dirt from sticking. Compared to the Samsung Galaxy Z Fold6, which we were able to briefly feel in the hand, Xiaomi feels more premium due to the thinner build. Overall, we like the look and the craftsmanship of this Chinese foldable even more.

With its thickness (5.6 mm when unfolded and 12.1 mm when folded), its sturdiness, and its foldable mechanisms, Samsung still feels more solid—but it doesn’t deliver anything like the great feel in the hand as the Xiaomi MIX Fold 4 does.

Samsung claims its model will last 200,000 folding cycles without any consequences. Xiaomi pushed that limit to 500,000 even with the thinner design. However, replacing the film on the internal display is easier with Samsung’s model, since it’s officially sold in our region and has an official service center here.

The crease on the internal display of Xiaomi MIX Fold 4 is visible, but during use it’s pretty negligible. You can even feel it, but compared to previous generations it’s clearly a step forward. During bending, you can barely hear any sounds.

Worth mentioning is that the large display inside is plastic, and with improper handling it can quickly show signs of wear. Pay attention to your nails, too, which can also visually damage the screen. It’s very delicate, precisely engineered electronics.

The controls—buttons for volume and the power button—are always on the right side of the device. That means they’re on the right half of the unfolded smartphone, or on the bottom layer if the phone is closed.

The power button also includes a fast and precise fingerprint scanner. On the bottom edge, located under the front display, you’ll find a USB-C port, a grille for the main, loudspeaker—very high quality—suitable even for watching videos, and a microphone. The second bottom edge has a slot for two nanoSIM cards. It’s almost unbelievable how these features fit into such a thin build.

On top of the Xiaomi MIX Fold 4 there’s even an IR port for controlling your home electronics. The second half has an additional speaker for creating stereo output. We do have a few reservations about the more demanding opening process. The phone is so thin that it’s hard to find the spot where you can simply open it. Also, the magnet that holds the folded smartphone together is quite strong. But you’ll get used to it.

Displays

Let’s start with the external display, which you’ll likely use more often even though it probably won’t be the main focus. It has a 6.56-inch diagonal, Full HD+ resolution (1080 x 2520 pixels) with a maximum brightness of 1700 nits (HBM), or a straight 3000 nits (peak). It’s a LTPO AMOLED panel with a 120 Hz refresh rate, support for HDR10+ content, and Dolby Vision technology. It’s slightly curved toward all four edges.

The Xiaomi MIX Fold 4 doesn’t have to be ashamed of itself—on the contrary. It would excel even among traditional smartphones. It’s great in every respect, including color reproduction. It has excellent viewing angles and a high touch response. When you put the included case on the phone, performing the back-gesture from the left side will be quite difficult due to the shape of the plastic frame of the cover.

In most cases, the back gesture will need to be done from the right side. It’s a minor thing, but it bothered us a bit. Without the case, of course, this wouldn’t be an issue, but this technological beauty needs protection.

After opening the device, you’ll be greeted with a large 7.98-inch display with a resolution of 2224 x 2488 pixels and an impressive 418 ppi pixel density—more than enough even for a diagonal like this. This Foldable LTPO AMOLED panel is just as good as the one outside.

It offers the same refresh rate of 120 Hz, maximum brightness of 1700 nits (HBM) and 3000 nits (peak), along with other quality features. Working or writing on such a big screen is a blast.

Not every app works well in this aspect ratio, and some games may have issues in particular. However, if we’re not mistaken, we didn’t run into the only problem, and for example Instagram is already optimized for foldable smartphones too.

The difference is in the number of supported colors. While the external display can show up to 68 billion colors, the internal one reproduces 1 billion. Honestly, we didn’t notice a significant difference. Xiaomi MIX Fold 4 is equipped with top-tier displays, which are one of its biggest highlights.

Power

The foldable smartphone Xiaomi MIX Fold 4 has been given the very best that the current market has to offer. The main role is played by the Qualcomm Snapdragon 8 Gen 3 chipset with 12 GB, or up to 16 GB of RAM. We tested the 12 GB version. That much memory is more than enough for today, and you definitely won’t need 16 GB for at least the next several years.

The UI runs at maximum smoothness and we didn’t come across even a single stuttering animation. The manufacturer has optimized the software perfectly. With demanding multitasking or gaming—probably due to the extremely thin body—you’ll likely feel some heat, but it wasn’t as noticeable as with the Xiaomi MIX Flip, which overheated during a 3DMark stress test. Xiaomi MIX Fold 4 passed the same test and also delivered a higher score across other benchmark apps.

We were wondering whether the phone would score higher in benchmarks in an open state thanks to better heat dissipation. However, in that case the number of points was lower—mainly because the graphics tests had to be rendered on a display with higher resolution.

Operating system

On Xiaomi MIX Fold 4 you’ll find a preinstalled operating system Android 14 with a graphical interface HyperOS in the Chinese version. That means you can use the phone only in English. The Chinese firmware can be used here, but you should pay attention to a few factors.

The first is that notifications are sometimes delayed, in worse cases by as much as dozens of minutes. Alerts from popular chat apps, including Messenger or WhatsApp, show a delay of roughly 10 – 20 minutes.

Extreme cases happened when the device was in standby mode for a long time. Then notifications didn’t come at all until the screen was turned on, or they arrived with hour-long delays. Some days, though, everything worked perfectly—it’s very inconsistent. Worth mentioning especially Slack, the team chat app. From it, we received notifications very rarely.

Energy optimization for background apps was turned off, and we also enabled Autostart for problematic apps, but it didn’t solve the issue of delayed notifications. The seller also installed Google Play Services in the system, so we wouldn’t look for the problem there either.

It’s simply a Chinese ROM that comes with this kind of drawback. The HyperOS itself is packed with useful features, and it also includes ones that are not allowed here—for example, recording phone calls. Some features are intended exclusively for China.

Preinstalled apps are localized mostly in Chinese and you can uninstall them. Compared to the global HyperOS version, you won’t find preinstalled games or social networks here. NFC payments work—you just need to download Google Wallet from the Play Store, set it as your default payment app, and you can start using the phone normally.

Cameras

On paper, the camera setup of the Xiaomi MIX Fold 4 is truly impressive. On the back, there are four cameras right away. There’s a 50 MPx main sensor with optical image stabilization. You also get a 12 MPx ultra-wide lens with a 120-degree field of view, a 50 MPx 2x telephoto with OIS, and a 10 MPx periscope telephoto with 5x optical zoom, which also has OIS.

On the front of the outer screen you’ll find a 16 MPx camera, and the inner display also has a front sensor with the same resolution. In total, you have up to 6 cameras. How can you use them in practice? Quite well. For photography, you can choose between two color profiles, Leica Authentic and Leica Vibrant.

The first-mentioned mode produces less vibrant, darker shots with a focus on contrast. It seems to us that in this case the mode tended to lose more detail, especially in the shadows, which is why in most cases we photographed with Leica Vibrant enabled.

The photos generally have high contrast, which especially hurts the detail in the darker areas of the images. The shots are a bit softer and less vibrant compared to the competition. If you’re into shots with colors close to reality, Xiaomi MIX Fold 4 won’t disappoint you with its results. All sensors perform very well; we’ve already seen a better 5x telephoto, but it still served nicely for shooting distant subjects.

The phone handles scenes with high dynamic range well. It can even surprise you at night. We also tried the “Pro” mode for shooting the Milky Way. With a 30 -second shutter, you can really work with it even for astrophotography. A RAW file is also generated, which you can then work with in editing programs.

We’re sharing an image in JPEG format with no additional edits. By the way, if we don’t specify under the sample photo which Leica mode it is, the photo was taken in the “Vibrant” style. The differences are sometimes so minimal that it doesn’t even make sense to add a second photo. You can record video in 4K at 60 fps or even 8K at 24 fps.

Video recording

Battery and charging

Xiaomi MIX Fold 4, with mixed use and switching between the outer and inner displays, delivers battery life of roughly 6 hours with the screen on within a single day. On less demanding days, at the start of which we had it fully charged and had the screens on for 3 hours and 42 minutes, after 24 hours the phone still had 46% battery remaining.

So if you’re a bit more modest and use the larger internal screen less, reality can be 7 hours SOT (Screen On Time). In our case, that means comfortable, 1.5-day battery life on a single charge. After one hour of watching YouTube videos on the inner, foldable display, 9% of power was used.

If you ever need to top up energy sooner, you’ll be pleased to know the model supports fast 67 W charging. There’s also a fast 50 W wireless power delivery. In the table below, you can see the breakdown of wired charging performance from 1% to 100%. At low battery levels, a hibernation mode will be offered, which will extend the overall battery life quite solidly in case of emergency. Of course, you can activate it earlier than right before the battery fully drains.

Connectivity

The foldable model Xiaomi MIX Fold 4 can boast modern connectivity. It has everything you’d expect from a premium smartphone. It’s a Chinese model, so it’s great that you can use it to connect to all the networks available here, including LTE band B20 and the most modern 5G networks.

Wi-Fi 7, Bluetooth 5.4, globally used GNSS services are also available, and you can also use the infrared port to control home or office electronics, NFC, or the USB-C connector, which is version 2.0. Call quality and connection to the mobile data network were excellent (tested with SIM cards from Orange, Radosť, and 4ka).

The phone is also known for its satellite SOS system, but it works only with Chinese carriers. What’s interesting, though, is that the satellite can be located in the sky even here in our country. The system will guide you to it.

Xiaomi MIX Fold 4: Final verdict

Xiaomi MIX Fold 4 pleasantly surprised us and impressed not only us, but also the people around us. That’s mainly thanks to the premium, thin design, enhanced by rounded display edges and great finishing on the back. We’re glad to see the build quality is very high and it doesn’t leave fingerprints or other smudges.

In a folded state, the Xiaomi MIX Fold 4 looks and feels like a traditional smartphone thanks to its minimal thickness. The system is fast and smooth; in most cases, the device doesn’t noticeably get warm, and the displays are high-quality and readable even in direct sunlight.

The operating system has a downside: the lack of the Slovak language and often delayed notifications. However, the Chinese HyperOS gets updates more frequently and earlier—especially if that’s something you care about.

Another advantage is strong battery life and fast charging, which doesn’t take even an hour. If you can live with the drawbacks of the Chinese firmware mentioned above and you really like this new release, we definitely recommend buying it. A global-market model almost certainly won’t arrive, so this is a unique opportunity to get your hands on a one-of-a-kind smartphone that turns heads.

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