We’ve been steadily improving the BookFusion plugin for KOReader, with a particular focus on making your BookFusion library feel more at home on your E-Ink devices. 

Our latest releases bring support for PDFs and comic books, more accurate highlights with colors, reading positions, richer book details, and several fixes that make syncing and updating more reliable.

New

PDFs & Comics Now Open Natively in KOReader

Your BookFusion library isn’t limited to EPUBs, and now your KOReader experience isn’t either.

PDF, CBZ, and CBR files in your BookFusion library now download in their original format and open natively in KOReader.

PDFs & Comics

That means you can download a PDF or Comic from BookFusion, read it using KOReader’s native reading experience, and still keep your reading position synced with BookFusion across your devices.

For PDFs, highlights also sync both ways. Create a highlight while reading on KOReader and it will sync back to BookFusion. Highlights created on your other devices can sync down to KOReader as well.

More Book Details

Previously, tapping a book gave you little more than its title and a couple of actions. Now you can actually get more details about the book before downloading or opening it.

Tap a book and you’ll see its:

• Cover and author
• Series information
• File format and download size
• Publication year and language
• Current reading progress
• Description

Book Details

Your Download, Read, and other actions remain right where you need them.

It’s a small change that makes browsing a large BookFusion library on KOReader much more useful.

Improvements & Fixing

More Accurate Highlights & Colors

Highlights should appear exactly where you made them.

We’ve improved how the plugin places and draws highlights in books where differences in text positioning could previously cause them to appear slightly off. The improvements apply in both directions: highlights you create in KOReader and highlights synced from BookFusion on your other devices. Colors made for highlights now also properly sync over to KOReader.

We’ve also corrected how highlight timestamps are handled. Highlight times are now sent in UTC, allowing BookFusion to display the correct local time regardless of your time zone.

Better Reading Position Sync

We’ve made several improvements to reading position syncing.

Reading positions coming from the BookFusion Web Reader now land more accurately in KOReader. In some books, a synced position could previously take you to the beginning of the chapter rather than the exact place where you stopped reading.

We also fixed an issue that prevented KOReader from determining your position on certain pages. When this happened, “Pushing reading position…” could remain on screen without completing.

You can now push your reading position from anywhere in a book. And if a sync fails, we’ll tell you instead of leaving you wondering whether anything happened.

More Reliable Updates and Network Handling

KOReader 2026.07 changed the archive API used by our updater, which meant older versions of the BookFusion plugin could fail with a “couldn’t extract the update” message.

We’ve updated the plugin to use KOReader’s current extraction API while retaining compatibility with earlier KOReader releases. We’ve also improved how the plugin handles an uncommon type of network failure. Instead of stopping the plugin with an error, BookFusion now handles the failure cleanly and reports that the request was unsuccessful.

Updating the BookFusion Plugin

If you’re already on BookFusion plugin v1.1.4 or later, updating is easy:

• Tools → BookFusion → Updates

If you’re using KOReader 2026.07 or later with BookFusion plugin v1.1.3 or earlier, there’s one extra step. Those older plugin versions use the updater API that KOReader removed, so they cannot install the newer release themselves.

Download the latest plugin release and replace your existing bookfusion.koplugin folder manually once. After that, future releases can install normally through the plugin.

If you’re on KOReader 2026.03 or earlier, you can continue updating normally from Tools → BookFusion → Updates.

You can find the latest release and installation files on BookFusion's KOReader plugin releases page.

Planned

These releases continue our work toward making KOReader a first-class BookFusion integration and not simply a way to download your books, but another device where your library, reading progress, highlights, and notes stay connected.

• Article support 
• Import existing books and highlights from KOReader

As always, keep the feedback, bug reports, and suggestions coming. They help us find the rough edges and make the experience better.

Happy reading!
— The BookFusion Team

Our latest BookFusion update brings device-based page numbers to reflowable EPUBs, adds more control over how you track your reading progress, and introduces Sleep Mode for audio. We’ve also packed in a long list of fixes across EPUBs, articles, PDFs, highlights, CarPlay, and more.

Page Numbers for Reflowable EPUBs

Yes! , you can now finally see device-based page numbers when reading reflowable EPUBs.

Unlike fixed-layout books, reflowable EPUBs adapt as you change your screen size, font, spacing, and other reading settings. BookFusion now gives you page numbers that work with that flexible reading experience, making it easier to keep track of where you are in a book.

**To switch to page numbers, simply tap the percentage progress indicator in the bottom-right corner of the reader.**You can also enable page numbers from Reading Progress under Advanced Settings.

https://reddit.com/link/1wntmu2/video/20um5monl6rh1/player

Prefer percentages? No problem. You can switch between page numbers and percentage progress at any time and use whichever feels most natural for you.

Sleep mode /Sleep timer

We’ve added Sleep Mode for Media Overlays and Text-to-Speech (TTS), making it easier to listen to books or articles before bed without letting playback continue long after you’ve fallen asleep.

When you turn on Sleep Mode, you can choose how you want playback to stop:

• After a set amount of time: Choose a time interval, and BookFusion will automatically stop playback when the timer ends.
• At the end of the current chapter: BookFusion will continue playing until the chapter finishes, then stop automatically.

Sleep Mode

This means you can start listening, get comfortable, and let BookFusion handle the rest. If you fall asleep, playback won’t continue indefinitely, making it much easier to return close to where you last remember listening.

Fixes & Improvements

We also spent plenty of time polishing the reading experience and squashing bugs across the app.

• Fixed Auto-scroll on iOS 27.
• Fixed bookmark restoration in image-only EPUBs.
• Fixed inconsistent Font Style application.
• Fixed SVG images not appearing in Article Clean Mode.
• Fixed other missing-image issues in articles.
• Fixed duplicate articles when sharing the same URL.
• Improved compatibility with highlights from the Article Browser Extension.
• Fixed a crash when updating from very old app versions.
• Fixed duplicate highlights.
• Fixed a rare crash when adding highlights.
• Corrected Clean Mode styling.
• Fixed inverted images in PDFs.
• Fixed the display of mathematical equations.
• Corrected downloaded-book ordering in CarPlay.
• Fixed rare missing styles in EPUBs.

The work continues

As usual please reach out to us with feedback, bug reports or suggestions. None of it happens without you, the readers who push us, report the rough edges, and remind us why we love this work.

And if you’re enjoying BookFusion, we’d really appreciate it if you took a moment to leave us a review on the App Store. Your reviews help more readers discover BookFusion and mean a lot to our team.

In the next few updates we will be focused on the following:

• Wrapping up and launching articles  
• Custom headers and footers ( clock, battery, reading time & more) 
• Any additional fixes for iOS 27
• Customisable Split View in reader for TOC, Highlights & Content 
• Surprise! (reply with what you want the surprise to be :))

Update to the latest version and tell us what you think.

Happy reading (and listening),

— The BookFusion Team

Our last two updates covered what shipped on Android and iOS. This one is the why: why we built Realistic Text-to-Speech (TTS) ourselves, and why we held it back until it was ready on all three platforms.

Synthetic narration has spent years sounding like a robot reading a phone book. That era ends today for your library.

Realistic Text-to-Speech (TTS) voices are now live across BookFusion for Web, iOS, and Android. Open a book. Pick a voice. Press play. Your eBooks, PDFs, and articles read back to you in voices that actually sound human.

No conversion workflow. No waiting on a rendered audio file. No pre-downloading audio. No GPU server to babysit. Just your books, speaking, on demand.

https://youtu.be/s-yamme5_4U?si=hY10g2qLEeDfizSQ

Two flavors, because readers listen in two very different places

We built realistic TTS twice over, because listening on a train with full bars and listening at 35,000 feet are not the same problem.

Streaming Voices

Streaming voices run on custom Kokoro models with our own tuning and refinements layered on top. We built and operate the TTS service ourselves, and that choice has one very direct benefit for you: subscription prices stay exactly where they are. No tokens to buy. No character caps. No metered minutes.  Advanced and Power readers get unlimited streaming across Web, iOS, and Android, in 9+ languages including English (US and UK), Spanish, French, Mandarin, Japanese, and Hindi.  

We stream Supertonic voices as well, which widens that to 31 languages: Arabic, Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish, Ukrainian, and Vietnamese

If you read in more than one language, or your books do, this is the part worth trying first.

Offline voices

Offline voices  run entirely on your device, and they are available on every plan — Free, Casual, Advanced, and Power. No internet. No pre-generating audio and waiting for a download. Your device does the work, sentence by sentence, as you read.

• On iOS , offline voices are powered by Supertonic, built directly into the app, with 31 languages supported. See more in our iOS update
• On  Android , offline voices come through the free BookFusion Voice companion app, with 100+ voices across 38+ languages. See more on BookFusion Android 2.23.10 and our BookFusion Voice Release 

Planes, subways, remote cabins, and that one dead spot on your commute are all fair game now.

*(Streaming is available on all three platforms. On-device offline voices are an iOS and Android. 

Why we ran our own service

We will be direct about the tradeoff, because it shaped the whole feature.

Realistic voice models are not free to run, and that cost has to land somewhere. Most services put it on you and meter it: pay per character generated, per minute listened, per credit consumed. That works fine for a paragraph. It works badly for a 400-page novel, and it turns "listen to another chapter" into an accounting decision.

 The other approach is quieter. A number of apps offer realistic voices for "free" by pointing at endpoints built for Microsoft Edge,  infrastructure they are not licensed to resell, and Microsoft has said as much on their own forum. We understand the appeal. We are not willing to build a core feature on a door someone else can close, because when it closes it is your listening that stops, mid-chapter, with no warning and no recourse.

So we took the slower road: instead of metering you or reselling someone else's API, we built and run the TTS service ourselves, tuned the models, and absorbed the cost. Unlimited stays unlimited, your subscription price does not move, and the voices keep working because they are ours to keep working.

And for the readers who would rather nothing leave their device at all, the offline voices exist precisely for that. Your book stays where it is.

The workflow this replaces

Readers who wanted genuinely good narration have been solving this themselves for a while now, with real ingenuity. Open-source projects like 

• Audiblez
• epub_to_audiobook and
• ebook2audiobook 
• and others

They also ask a lot of you: install dependencies, manage a command line, download models, configure environments, sometimes rent GPU time. Then generate the whole audiobook up front, wait for it to finish, and move the files onto the device you actually read on. If you edit the book or want a different voice, you do it all again.

BookFusion collapses that into four steps:

1. Open an eBook, PDF, or article.
2. Tap Listen/Play.
3. Choose a streaming or offline voice,  preview it first, nobody should commit to a voice unheard.
4. Play.

The narration is generated as you listen. No scripts, no leftover audio files, no second copy of your library to keep in sync.

It is part of the reader, not a separate app

Realistic voices are not a conversion utility bolted on the side. They live inside the BookFusion reader, which means everything else keeps working while you listen: your synced library, your reading progress, your highlights, your notes, your bookmarks.

Read three chapters on the Web at your desk, keep listening on your phone during the walk home, and pick up the text again that evening exactly where your ears left off. One library. One position. No juggling.

We also spent an enormous number of hours on the listening experience around the voices — sentence-level skip controls, a rewritten sentence tokenizer for more natural pacing, sentence highlighting that follows the narration, TTS in PDFs, footnotes that stop interrupting the flow. Great narration is only half the craft; the reader around it has to keep pace.

Who this is for

Text-to-Speech is often filed under accessibility, and it absolutely belongs there,  for readers with low vision, dyslexia, or eye strain, a natural-sounding voice is the difference between finishing a book and abandoning it.

But it is not only that. It is also for the reader with their hands in the dishwater, the language learner who needs to hear pronunciation rather than read it, the student pushing through a dense chapter for the second time, the commuter, the runner, and the person who simply likes being read to.

We are not trying to replace human narrators. A professionally performed audiobook is a genuine creative work, and nothing synthetic matches it. What realistic TTS does is give a voice to the enormous number of books, papers, and documents that will never get an audiobook edition at all , including the ones you wrote, scanned, or saved yourself.

Start listening

Open BookFusion, pick a book, tap Listen, and spend a few minutes auditioning voices. We think you will notice the difference in the first paragraph.

This is the first release of something we intend to keep sharpening, more voices, more languages, a sleep timer, and a few things we are not ready to talk about yet. Tell us which voices you love, which ones read a name wrong, and what your language needs are. Some of our best work has started as a reader's complaint 🙂

Write to us at support@bookfusion.com or reply below.

Happy reading (and listening),

–The BookFusion Team

Today, we are excited to announce the launch of BookFusion Voice, a new Android text to speech engine that brings natural-sounding neural voices directly to your device.

BookFusion Voice makes it easier to listen to books, articles, documents, and other text using high-quality AI voices that work offline after download. Once a voice is installed, speech synthesis happens locally on your Android device, so your text never leaves your device.

Whether you use BookFusion for reading, rely on text to speech for accessibility, or simply prefer listening while you read, BookFusion Voice gives you more control, more privacy, and more choice.

https://www.youtube.com/watch?v=WHqfugDW_uk

Getting started with BookFusion Voice

Getting started is simple.

1. Install BookFusion Voice on your Android device.
2. Open the app and browse the voice catalog.
3. Filter by language and quality.
4. Preview voices using native language sample sentences.
5. Download the voices you want to use.

If you use BookFusion, you are done. BookFusion will automatically detect your installed voices so you can start listening right away.

For step by step instructions, screenshots, setup guidance, and troubleshooting tips, visit the official BookFusion Voice tutorial and documentation:

BookFusion Voice: Offline Realistic Voices on Android

BookFusion Voice APK - https://bookfusion-desktop-updates.s3.us-east-1.amazonaws.com/bookfusion_voice_1_2_0.apk

BookFusion Reader APK - https://bookfusion-desktop-updates.s3.us-east-1.amazonaws.com/com.bookfusion.android.reader_Android_v.2.23.7_c.223071-release-protected.apk

Natural voices that work offline

BookFusion Voice includes two voice families:

• SUPERTONIC voices are expressive, premium-quality multilingual voices. Each voice can speak 31 languages from a single download, allowing you to switch between voices and languages without downloading a separate model each time.
• PIPER voices provide a large catalog of 150+ voices across 40+ languages. Piper voices are available in low, medium, and high quality tiers, so you can choose the right balance between naturalness, performance, and device capability.

Together, these voice families give Android users access to more than 160 voices across 40+ languages.

Built for real-world listening

Not every voice performs the same on every Android device. Some voices sound more natural but require more processing power, while others are lighter and faster.

BookFusion Voice automatically tests each downloaded voice on your device, then shows how fast it runs. You will also see a clear warning when a voice may be too demanding for smooth, gap-free playback.

This helps you choose voices that work well on your actual device before relying on them for longer listening sessions.

Performance Note:

BookFusion Voice runs speech synthesis directly on your Android device. This is what makes offline listening and private, on-device text to speech possible, but it also means performance depends on your device’s processor, memory, and the voice you choose.

Some voices require more processing power than others. Supertonic voices and high quality Piper voices can sound more natural, but they may not run smoothly on lower powered devices. If a voice test shows poor performance, we strongly recommend using a low or medium quality Piper voice instead. These voices are lighter, faster, and often provide a much better listening experience on less powerful devices.

We have seen some early app store ratings reflect this misunderstanding. Poor performance from a demanding voice on a low powered device does not mean BookFusion Voice is low quality. It usually means that the selected voice is too demanding for that specific device.

That is why BookFusion Voice includes on-device performance testing. Before using a voice for longer listening sessions, you can test it, see how fast it runs, and choose the best option for your device. Selecting the right voice for your hardware is the best way to get smooth, reliable, gap-free narration.

Seamless integration with BookFusion

BookFusion Voice works especially well with the BookFusion Android app.

Once you download a voice, BookFusion detects it automatically. No extra setup is required. When used together with BookFusion, voices are pre-buffered ahead of time to help provide seamless narration with fewer pauses between paragraphs or pages.

That means you can download a voice in BookFusion Voice, open BookFusion, and start listening to your books and documents with a more natural read-aloud experience.

Works with other Android apps too

BookFusion Voice is also a standard Android text to speech engine. That means it can be used with other Android apps that support text to speech, including book readers, accessibility tools, TalkBack, navigation apps, and more.

To use it outside of BookFusion, install your preferred voices, then go to Android Settings, open Text-to-Speech settings, and select BookFusion Voice as your preferred engine.

Designed with privacy in mind

Privacy is one of the biggest advantages of offline text to speech.

With BookFusion Voice, all speech synthesis happens locally on your device. Your text is not sent to a server for processing. The app only connects to the internet to fetch the voice catalog and download voice files.

This makes BookFusion Voice ideal for users who want a private, offline listening experience for books, articles, documents, and other personal content.

Accessibility-first design

BookFusion Voice was also designed with accessibility in mind. The app includes full screen-reader labelling throughout and works with Android accessibility tools such as TalkBack.

Users can preview voices before downloading, filter by language and quality, view download sizes, adjust speech speed from 0.5x to 2.0x, and select the voices that best match their listening needs.

With BookFusion Voice, we are making natural, private, offline text to speech more accessible to readers everywhere.

If you love e-readers, there’s a good chance you own more than one.

Maybe you read on a Kobo at home, a Kindle when you travel, a Boox or PocketBook for PDFs and manga, and your phone when you only have a few minutes. Each device has its own strengths but until now, keeping your books, reading position, and highlights together across them could feel like a workaround.

• Your page was on one device.
• Your highlights were on another.
• And your library lived somewhere in between.

Today, we’re excited to officially launch the BookFusion KOReader Plugin, a new way to connect KOReader directly to your BookFusion library.

With the plugin, you can browse your BookFusion library inside KOReader, download books over the air, and keep your reading position and highlights in sync across KOReader devices and the BookFusion apps on Web, iOS, and Android.

No cables. No manual transfers. No file hashes . No walled gardens.

Just your content, wherever you want to read.

How to Get Started

To use the BookFusion KOReader Plugin, you’ll need:

• KOReader 2026.03 “Snowflake” or later
• A BookFusion account
• The BookFusion KOReader plugin

Start with the setup guide here:

BookFusion KOReader Plugin Guide
https://docs.bookfusion.com/docs/KOReader/

The guide walks you through installing the plugin, linking your device, browsing and downloading books, syncing reading position and highlights, setting up gestures, and troubleshooting common issues.

Built for Readers Who Use More Than One Device

KOReader is one of the most powerful open-source reading apps available for e-ink and Android devices. It is popular with readers using devices such as Kobo, Kindle, PocketBook, reMarkable, Boox, and other e-readers that support KOReader.

BookFusion is built around a simple idea: your books, articles, highlights, notes, reading progress, and reading life should travel with you.

The KOReader plugin brings those two worlds together.

Once installed and linked to your BookFusion account, the plugin lets you open KOReader, go to the BookFusion menu, and access your library directly from your device.

You can browse by:

• Currently Reading
• Shelves
• Smart Shelves
• Tags
• Series
• Your full library

Then download the book you want and start reading.

What You Can Do with the BookFusion KOReader Plugin

Browse and Download Your Library from KOReader

Open the BookFusion plugin inside KOReader and browse your library without needing to connect your device to a computer.

You can find the book you want, choose where to save it, and download it directly to your e-reader.

For readers with carefully organized libraries, metadata such as series, tags, and covers are included when the book is downloaded, helping KOReader display your books more usefully on device.

Pick Up Where You Left Off

Read on one device, sync your position, and continue on another.

Finish a chapter on your Kobo. Later, open the same book on your Boox, Kindle, PocketBook, phone, tablet, or the web, and continue from where you left off.

The plugin supports both manual sync and auto-sync, so you can decide how much control you want.

Sync Highlights Across Devices

Highlights made in KOReader can sync back to BookFusion, making them available across your connected devices and BookFusion apps. (Exports to Obsidian, Notion & More)

This is especially useful for readers who use e-ink devices for deep reading but still want access to their highlights later on web or mobile.

Use Gestures for Faster Syncing

For readers who prefer fewer menus, the plugin adds BookFusion sync actions to KOReader’s Gesture Manager.

You can assign actions such as pushing progress, pulling progress, or syncing highlights to your preferred taps or swipes.

Track Reading Time

Reading time in KOReader can also count toward your BookFusion reading totals.

That means time spent reading on your e-reader becomes part of your broader reading history in BookFusion, alongside time spent in the BookFusion apps.

Early Reader Feedback

Before making the plugin generally available, we shared it with beta readers and iterated based on their feedback. Readers helped identify bugs, test sync behavior across devices, and suggest improvements for future releases.

Here are some of the comments we received during testing:

>Syncing is very fast.

>The new beta worked well for annotation sync. On one EPUB I made more than 30 highlights and they synced correctly between two Boox devices.

>It works great on my PocketBook and Kobo. Thanks.

>Enjoying this plugin so far.

>Great Plug-in. I have connected KOReader on my Kobo to my BookFusion account, and it works flawlessly.

>“Latest update, so far, appears to be working perfectly on PineNote, Boox Nova Air C, and Boox Palma. ”

This is exactly why we wanted to build the plugin with the community: real readers, real devices, real libraries, and real reading workflows.

What’s Supported Today

The first public release focuses on the core reading workflow:

• Browse your BookFusion library from inside KOReader
• Download EPUB books directly to your device
• Sync reading position
• Sync highlights
• Use manual sync or auto-sync
• Assign sync actions to KOReader gestures
• Track reading time
• Download books with updated series, tags, and cover metadata

Today, the main sync focus is books, reading position and highlights.

Thank You to Our Beta Readers

Before this public release, the BookFusion KOReader Plugin was shaped by readers who generously tested early builds, reported issues, shared device-specific feedback, and helped us understand how the plugin performed across real reading workflows.

To everyone who installed the beta, synced books across devices, tested highlights, reported bugs, suggested improvements, and patiently tried new versions — thank you.

What’s Coming Next

This launch is an important milestone, but it is not the end of the KOReader roadmap.

Based on reader feedback, we are already looking at several improvements, including:

• PDF support
• CBZ/CBR support
• Downloading multiple books in one action (future)
• Better sorting options when browsing books
• Downloading clean article EPUBs
• Importing existing KOReader books & highlights into BookFusion
• Additional improvements

As always, we’ll continue listening to reader feedback and improving the experience over time.