Any and all advice, guides, and reviews are unbiased and based on my personal experience. If you buy through affiliate links, I may earn commissions, which helps support my website. This does not have an impact on posts or my opinion of any reviewed products. If you find this post helpful and want to say thanks, please buy me a coffee or take a look at my book on Amazon. It keeps this page ad-free. Thank you!
Great news! The XTEINK X4 is now available direct on Amazon.com
Next day delivery for Prime. Faster shipping than AliExpress!
If you’re on this page, you probably know all about XTEINK a company that makes small eInk devices that can, quite literally, attach to the back of your phone.
The most popular XTEINK device is the X4 (see the best guide for XTEINK X4 owners here; having issues with your X4, see my XTEINK X4 troubleshooting guide) and in February 2026, XTEINK started shipping the X3 (see my thoughts on the XTEINK X3 here). But! and this is the interesting bit, sometime in 2026 we’re getting an XTEINK S4… what is the S4? It’s the successor to the X4, here’s what is known based on what I have found digging through random Chinese social media posts and information from XTEINK themselves.
In March 2026, XTEINK confirmed the S4 will be released and final design is locked. See the updated image on the right. I am hoping this means pre-orders will open soon, so they can start production runs.
There are also rumors coming out of China of a X4 v2, I am not sure if that’s just mishyped S4 rumors or something different. Based on various social media posts, XTEINK has hinted at a backlight offering for the X4 (it’s likely we’ll have a backlight on the S4).
I’ll post more on the S4 and X4 v2 as I learn more. For now, the only model directly available with US shipping is the X4 on Amazon.com
Breaking News: A backlight solution is being tested! Yay!
XTEINK S4 Specifications and Features
Here’s the (currently) known specifications and features of the XTEINK S4:
- new software, likely Android-based
- app support, including Kindle app!
- backlight (possibly! in testing!)
- touchscreen
- WiFI + Bluetooth
- single front buttons
- USB C charging (same as X4)
- matte plastic, in black and white
- real time clock
- 4.3″ screen size (same as X4)
- weight 100g (early prototype, subject to change)
- thickness 6.9mm (early prototype, subject to change)
XTEINK S4 v X4 Comparison
If you’re wondering how the S4 compares to the X4, there are some previews leaked on Chinese social media. See the imagfe on the right, which shows the S4 is actually slightly more compact than the X4 but a fraction thicker.
From the various videos, it’s possible the S4 is Android based vs the X4 which runs XTEINK OS (or Crosspoint if you prefer custom firmware). Early previews the S4 showed Android Developer Options (in settings). The final hardware build doesn’t really make it clear, but the support for Chinese reader apps suggests Android.
There is a single front button which operates like a home button on older iPhones. There is a power button (top right).
The XTEINK S4 may have a microSD slot, it looks like it does on the top left side, using a tray type. It’s really hard to be 100% sure on this, as it could also be a button and reset pin hole. I’m really hoping it’s a microSD slot.
XTEINK S4 Software / Firmware
The current videos and screenshots are of Chinese firmware, and there’s some new features in the XTEINK S4. If you look at the leaked S4 image on this page, the main home screen options are (from top left, left to right):
- Bookshelf
- Settings
- File Manager
- WiFi Book Transfer
- Free Tomato Novels
- WeChat Reading
No, Free Tomato Novels is not a mistranslation. Tomato Novels is a Chinese fiction site “番茄小说” (Fanqui Xiaoshuo), sort of Wattpad-like. It’s owned by ByteDance, yep, the company behind TikTok. So, this it will have store front integration, which is absent on the X4.
The store front integration is also confirmed by WeChat Reading. This is owned by Tencent and has a large library of licensed books, web novels, comics, and audiobooks. It integrates into WeChat, a ubiquitous Chinese everything app. There really isn’t an equivalent to WeChat in English-speaking markets.
What this means in practical terms is the S4 will be able to browse a page to actually load the store front. What the international version will offer (assuming there is one) is hard to know. Especially when Tomato Novels and WeChat are not DRM locked. Nearly all English-language store fronts have DRM locked books. Maybe the international version won’t have a store front? Or they will strike a deal with Wattpad. It’s Android based, so they could offer the Android version of the Kindle store.
XTEINK S4 Latest Hardware Preview – March, 2026
This is the final hardware preview, shared March 25th 2026. The hardware is locked down! We may get the XTEINK S4 soon!
XTEINK S4 Sneak Peak Development Preview
If you’re interested, here’s a video preview of an early development build of the XTEINK S4. This shows you how little has changed since the prototype to now and the clearesty view of the OS. The text in the orange bubble confirms it’s the S4 preview. The main development board is connected via the ribbon cable, so this is very much a prototype and subject to change and the development board was obscured with the white lines in the original video.
XTEINK S4 Release Date
In November 2025, XTEINK posted on the Chinese social media app Rednote, that the S4 will be released early 2026. Given the X3 is shipping March 2026, and XTEINK also did pre-orders for the X3 in 2025, I think the earliest we can expect it is in around late mid 2026 but I am hopeful pre-orders open early April. Chinese New Year Holidays in 2026 is Feb 15-23rd and China shuts down during that period, and X4’s and X3’s are experiencing production delays – so mid 2026 is the most optimistic date.
I’ll keep this post updated as I learn more.
FYI, the the XTEINK X4 is now available direct on Amazon.com
Some of my other posts about XTEINK devices:
XTEINK X4
- The best tools, hacks, and more for XTEINK X4 owners
- Ultimate XTEINK X4 FAQ (Unofficial)
- XTEINK X4 troubleshooting, fix common problems and issues.
- How to change the XTEINK language from Chinese to English
XTEINK X3
XTEINK S4
XTEINK Wallpaper eInk Card
XTEINK YouTube Videos
Any and all advice, guides, and reviews are unbiased and based on my personal experience. If you buy through affiliate links, I may earn commissions, which helps support my website. This does not have an impact on posts or my opinion of any reviewed products. If you find this post helpful and want to say thanks, please buy me a coffee or take a look at my book on Amazon. It keeps this page ad-free. Thank you!