X3, X4 and X4 Pro

RetroInk runs on three Xteink readers. They share the reading engine, the Library, the dictionary, transfers, syncing and the System 6 look, but the hardware is different, so some features only exist on some of them. This page is the full list: what each device has, what works where, and why when it doesn’t.

Legend. ✅ works · 🟨 works, with a difference · ➖ not available. New marks things that arrived with the X4 Pro in 0.6.0.

Which file is for which device

	X3	X4	X4 Pro New
Firmware file	`firmware-x3-x4-v*.bin`	`firmware-x3-x4-v*.bin`	`firmware-x4-pro-v*.bin`
Same file as	the X4	the X3	none, its own build
Runs on the other devices	➖	➖	➖
Updates over Wi-Fi	✅	✅	✅

The X3 and X4 share one file because they share a processor family; the firmware tells them apart when it starts. The Pro uses a different processor, so it has its own file, and the reader refuses a file built for another device.

The hardware

This is the reason behind almost every difference further down.

	X3	X4	X4 Pro New
Screen	792 × 528 e-ink	800 × 480 e-ink	800 × 480 e-ink
Processor	ESP32-C3	ESP32-C3	ESP32-S3 with 8 MB extra RAM
Touch screen	➖	➖	✅ multi-touch
Front buttons (Back, Select, Left, Right)	✅	✅	➖
Side rocker (Up, Down)	✅	✅	🟨 two edge keys
Home key	➖	➖	✅ capacitive
Power button	✅	✅	✅
Frontlight	➖	➖	✅ warm and cool
Clock chip (keeps time while asleep)	✅	➖	✅
Motion sensor	✅	➖	➖
Battery gauge	chip	voltage reading	chip

Features, device by device

Reading

Feature	X3	X4	X4 Pro	Why
EPUB, TXT and XTC reading	✅	✅	✅	Shared code
Fonts, SD card fonts, margins, layout options	✅	✅	✅	Shared code
Dictionary lookup	✅	✅	✅	Shared code
Bookmarks, footnotes, chapters, go to %	✅	✅	✅	Shared code
Clippings and highlights	✅	✅	✅	Shared code
Highlight by holding a word and dragging New	➖	➖	✅	Needs a touch screen
Turn pages with buttons	✅	✅	🟨 edge keys	The Pro has no front or side-rocker buttons
Turn pages by tap or swipe New	➖	➖	✅	Needs a touch screen
Tilt to turn pages	✅	➖	➖	Needs a motion sensor, which only the X3 has
Pinch to change font size, twist to rotate New	➖	➖	✅	Needs a multi-touch screen
Auto page turn	✅	✅	✅	Shared code
Page refresh on screen change	fast	half refresh	half refresh	The X3 has a different panel controller from the X4 and the Pro

Library, files and sync

Feature	X3	X4	X4 Pro	Why
Library with shelves, custom shelves, sorts, A–Z	✅	✅	✅	Shared code
Browse and move files in the web file manager	✅	✅	✅	Wi-Fi
Move Selected (many files at once)	✅	✅	✅	Wi-Fi
OPDS, Calibre, WebDAV, Nearby transfer	✅	✅	✅	Wi-Fi
KOReader progress sync	✅	✅	✅	Wi-Fi
Obsidian clipping sync	✅	✅	✅	Wi-Fi
USB Drive (SD card as a drive over USB-C) New	➖	➖	✅	Needs USB mass-storage support that the Pro’s S3 processor has and the X3/X4’s C3 does not
Update over Wi-Fi	✅	✅	✅	Each release carries both files

Look and feel

Feature	X3	X4	X4 Pro	Why
System 6 theme, 16 desktop patterns	✅	✅	✅	Shared code
O \| I rocker on/off switches	✅	✅	✅	Shared code
System 6 alert dialogs	✅	✅	✅	Shared code
Other themes (Lyra, Carousel, Minimal, Dashboard)	✅	✅	✅	Shared code
Classic and Rounded themes	✅	✅	➖	Not offered on touch devices
Bottom key bar	✅ four keys	✅ four keys	🟨 one or none	The Pro uses touch and the title bar’s Back box instead
Tappable Back box in every window New	➖	➖	✅	Needs a touch screen
Remap the front buttons	✅	✅	➖	The Pro has none
Sunlight Fading Fix	✅	✅	➖	Button devices only
Quick brightness and warmth panel (swipe down) New	➖	➖	✅	Needs a frontlight and a touch screen
Frontlight settings and wake behavior New	➖	➖	✅	Needs a frontlight

Time and date

The clock chip is what separates the X4 from the other two. Without it the reader has no idea what day it is after it sleeps.

Feature	X3	X4	X4 Pro	Why
Date and time kept while asleep	✅	➖	✅	Needs the clock chip
Clock in the header and reader	✅	➖	✅	Needs the clock chip
Date, time and time zone settings, sync from Wi-Fi	✅	➖	✅	Needs the clock chip
Clock desk accessory	✅	➖	✅	Needs the real time
Moon Phase, Earth, Desk Calendar	✅	🟨 pick a date	✅	The X4 asks you for a date and saves it
Calendar Sync	✅	🟨 for the date you set	✅	The X4 shows events for the date it was given
Today sleep screen	✅	➖	✅	Needs the real date
Book Status sleep screen	✅	➖	✅	Needs the real date
Book + Week and Reading Year sleep screens	✅	➖	✅	Needs the real date
Moon, Earth, Desk Calendar, Calendar Day sleep screens	✅	🟨 draw your saved date	✅	The X4 uses the date you picked
Daily reading goal and countdown badge	✅	➖	✅	The goal resets each calendar day
Focus Session	✅	🟨 pauses while asleep	✅	The X4 loses time when it powers off
Per-book reading stats	✅ with dates	🟨 single screen, no dates	✅ with dates	Dated figures need a clock
Automatic stats backup	✅	➖	✅	Backups are dated; Backup Now works everywhere, numbered on the X4
Timestamps on highlights	✅	➖	✅	Needs the clock
Frontlight schedule New	➖	➖	✅	Needs a frontlight and a clock

Desk accessories and games

Feature	X3	X4	X4 Pro	Why
Focus Session	✅	✅	✅	Shared code
Puzzle	✅	✅	✅	Shared code
Moon Phase, Earth, Desk Calendar, System Info	✅	✅	✅	The X4 asks for a date
Clock	✅	➖	✅	Needs the real time
Marble Maze	✅	➖	➖	Needs a motion sensor
Minesweeper New	➖	➖	✅	Plays by touch

What each device gets

X3. Everything except touch-only features. It is the most complete button device: it has the clock chip and the motion sensor, so it gets the Clock, all the date-driven sleep screens and goals, Marble Maze and tilt page turn.

X4. The same reading, Library, syncing and look as the X3, but with no clock chip and no motion sensor. Date-driven features are either asked for (Moon Phase, Earth, Desk Calendar) or left out (Clock, the stats sleep screens, daily goals, header clocks). Marble Maze and tilt page turn are not available. More on the X4.

X4 Pro. New A touch-first RetroInk on a touch screen, with a clock chip and a frontlight. It gets the date features of the X3, plus the quick brightness panel, touch reading gestures, hold-and-drag highlighting, USB Drive and Minesweeper. It has no motion sensor, so no Marble Maze or tilt page turn, and no front buttons, so no button remapping. See RetroInk on the X4 Pro.

Firmware size

Both files fit the 6.55 MB app partition with room to spare.

File	Size (0.6.0)
`firmware-x3-x4-v0.6.0.bin`	about 6.44 MB
`firmware-x4-pro-v0.6.0.bin`	about 6.39 MB

Not supported

The X4 Classic is not supported yet. It uses the same family of processor as the Pro but has buttons only, and it has not been built or tested with RetroInk.