KyBook 3 Alternatives for iPhone & iPad (2026): The Migration Guide

You open KyBook 3, and something is off. Maybe your OPDS catalog will not connect anymore. Maybe the Calibre server that synced fine two iOS versions ago now just times out. Maybe the app launches slower, glitches on layout, or quietly forgets a reading position. Nothing has crashed hard enough to force you out, so you keep nursing it along. But the app you built your entire reading setup around is decaying, one iOS release at a time, and you can feel it.

If that is you, you are not imagining it, and you are not alone. KyBook 3 earned a devoted following among power readers for a specific bundle of things: OPDS catalogs, self-hosted library access, deep typography, a format list longer than almost anything else on iOS, and the plain fact that you owned your files. Then it stopped. This guide is written for exactly that person, the orphaned KyBook power user: what actually happened to the app, which of its capabilities you can get back in 2026, where the honest gaps are, and how to move your whole library across without losing anything.

I'm Petr Jahoda, and I make justRead. So read this as a maker's guide, not a neutral review. I am not going to pretend I have no stake: I built justRead partly because this whole category, the serious side-loading reader with OPDS and Calibre at its core, was left to rot after KyBook and Marvin stopped shipping, and I wanted the successor I wished existed. I still test the other apps on my own iPhone and iPad, I recommend them by name where they beat justRead, and I state justRead's missing formats plainly below. If comics or FB2 are half your library, I will point you elsewhere in this very post.

This post was fully rewritten and expanded in July 2026.

What happened to KyBook 3?

KyBook 3's last release was version 0.7.8, shipped in February 2019. That is not a typo and it is not a recent gap. As of 2026 the app has gone more than seven years without a meaningful update. It was a roughly $3.99 one-time purchase, it still carries a genuinely strong App Store rating from its actively maintained years, and on paper it still targets iOS 11 and up on 64-bit devices. So it can still install and launch for a lot of people, which is exactly what makes its decay easy to ignore until it bites you.

Here is the concrete decay signal worth taking seriously. On newer iOS versions, KyBook 3's OPDS and Calibre connections have been reported breaking, while the older KyBook 2 kept connecting under the same conditions. That is a documented regression, and it is the worst possible kind for a reader like this. The networking layer that made KyBook special is the part rotting first. When Apple changes how apps handle file access, TLS, or background networking, a maintained app ships a point release and moves on. An app frozen since 2019 simply loses that capability, permanently, because there is no one left to fix it.

That is why "does it still launch" is the wrong question. Your books, your reading positions, your highlights, and your catalog connections all live inside this one app. An unmaintained reader is a library you cannot trust: it keeps working right up until an iOS update decides it does not, and then it stays broken. If KyBook is still limping along for you today, treat that as borrowed time, not a stable setup. The good news is that migrating now, while the app still launches and can still export your files, is far easier than migrating later after an update has locked you out.

What KyBook users actually relied on

Before comparing replacements, it helps to name what made KyBook worth defending, because most people searching for an alternative are not asking for "any ebook app." They want specific capabilities back. Run down this checklist and mark the ones you personally care about, because the right replacement is the one that covers your items, not the one with the longest spec sheet:

• OPDS catalogs. Browsing and downloading books straight from a catalog URL, including public libraries like Project Gutenberg and your own self-hosted servers.
• Self-hosted library access. Connecting to a Calibre server (or calibre-web, Kavita, Komga) on your own network instead of buying everything from a store.
• Format breadth. KyBook read EPUB, PDF, FB2, DJVU, MOBI, and AZW3, plus CBR/CBZ comics and audiobooks. Mixed collections were its home turf.
• Deep typography and user CSS. Fonts, margins, spacing, and CSS-level control over how a page rendered.
• Custom fonts. Loading your own typefaces, not just picking from a fixed list.
• Text-to-speech. Having books read aloud on the go.
• Owning your files. No store lock-in, no DRM wall around books you already owned.

For most former KyBook users, OPDS and self-hosted access sit at the very top, custom fonts and typography right behind them. Keep your own ranking in mind as you read the mapping below.

KyBook did X, here is what replaces it

This is the core of the guide: a feature-by-feature map from what KyBook gave you to what covers it in 2026. Here is the honest side-by-side first, then the detail underneath.

Custom fonts

KyBook let you load your own typefaces, and for a lot of readers that alone was the reason to stay. This is where the sharpest difference in the whole field shows up. justRead ships with over 200 fonts built in and, more importantly, lets you import your own fonts from a ZIP file, so the exact typeface you tuned KyBook around comes with you. It also has an original-font mode that respects the publisher's embedded fonts when you want them. The reason to single this out: Yomu, which otherwise gets recommended as a KyBook alternative, cannot load custom fonts at all. If bringing your own type is non-negotiable, that one fact rules out the most common suggestion and is the clearest argument for justRead specifically.

Typography and CSS-level control

KyBook's draw was control over the page, often through CSS. justRead approaches the same goal with direct controls rather than a stylesheet, and it adds something KyBook did not have: per-book settings. You can pull margins all the way to true zero, adjust line, letter, and word spacing independently, toggle hyphenation, and override the publisher's styling when a book fights you, and then justRead remembers those choices per book instead of forcing one global look. It also does full-RGB text and background colors, including a true black for OLED screens. So this is not merely a match for KyBook's typography, it is finer-grained on the axis most power readers care about.

OPDS catalogs

OPDS is where KyBook earned its reputation, and it is the first thing to test in any replacement, especially since KyBook's own OPDS is the part reported breaking on new iOS. justRead is built around this need and its OPDS still works in 2026. You add a catalog by URL, browse it in the app, and search the server directly instead of downloading everything first, with category browsing and server-side search so large catalogs stay fast. Project Gutenberg and the Internet Archive are built in, so tens of thousands of free public-domain titles are there the moment you install it. For self-hosters, it connects to custom OPDS servers including Calibre's built-in feed, calibre-web, Kavita, Komga, and COPS. If you ran one of those behind KyBook, the move is mostly re-entering the URL. The full walkthrough lives on the OPDS reader page.

Calibre

A lot of KyBook users were really running a Calibre setup and using the app as the phone-side client. KyBook did this as a one-way OPDS download. justRead offers a more direct route: a two-way Calibre Content Server connection. It finds your server over Wi-Fi automatically, or you enter it by hand, then shows New, Changed, and Synced badges so you pull only what actually moved. Crucially it syncs both directions, writing reading progress, ratings, finish dates, and stats back to Calibre, so the desktop library and the phone stay in agreement instead of drifting. It handles multiple libraries and HTTP Digest authentication, and it syncs PDFs alongside EPUBs. For a former KyBook user this is often the single biggest upgrade in the move. The Calibre sync workflow covers discovery, badges, and exactly what gets written back.

Cloud storage

KyBook read from Dropbox and WebDAV. justRead reads straight from iCloud, Dropbox, Google Drive, and OneDrive, so if your masters live in any of those you can point the app at the folder and read from there, keeping a single copy of each book rather than duplicating your whole library into app storage.

Audiobooks and read-along narration

This one used to be a genuine gap and is not anymore, which is why it belongs in a KyBook migration guide specifically. KyBook handled audio, and readers who used it as an audio player assumed they would lose that. justRead now has a built-in audiobook player with variable speed, chapter navigation, and a sleep timer, plus read-along narration for EPUB3 books that ship media overlays, so the text highlights in time with the voice. That makes audio a real parity point rather than a reason to keep KyBook installed.

Highlights and annotations

KyBook let you highlight, but getting those notes back out was the weak spot. justRead offers six highlight colors and, more importantly, exports to Readwise and to Markdown, so your annotations are portable rather than trapped in one app the way KyBook's effectively were. This is a straight gain over the app you are leaving.

Reading statistics

KyBook had essentially nothing here. justRead tracks reading sessions, streaks, a periodic Reading Recap, and a reading-speed trend (in beta). It is not a reason to switch on its own, but it is a pleasant upgrade once you are across. The reading statistics page shows what it captures.

Active development

Everything above rests on this. KyBook has shipped nothing since February 2019. justRead is actively developed with a public roadmap, which is the one thing an abandoned app can never offer and the reason its OPDS still connects when KyBook's is breaking. An app that ships updates keeps working as iOS shifts underneath it; a frozen one degrades until it stops.

The honest gaps: where justRead does not replace KyBook

Credibility means saying this plainly. justRead does not do everything KyBook did, and for some libraries these gaps are dealbreakers. Know them before you switch.

• No comics. justRead does not read CBR or CBZ. If part of your library is comics or manga, use a dedicated comic reader such as Panels or Chunky for those, and treat justRead as your reflowable-text reader. This is a companion setup, not a full replacement, if comics matter to you.
• No MOBI, AZW3, DJVU, or FB2. justRead reads EPUB and PDF only. KyBook's format breadth was real and justRead does not match it. The fix is to convert those files to EPUB in Calibre before you migrate; Calibre does FB2 to EPUB cleanly and in bulk, and handles MOBI and AZW3 conversion too. Do this while KyBook still launches so you are not stuck later.
• No text-to-speech. KyBook could read books aloud with TTS. justRead does not have TTS. Note this is separate from its audiobook player: justRead plays actual audiobook files and EPUB3 media-overlay narration, but it will not synthesize speech from a plain EPUB. If you specifically relied on TTS, that is a real loss to weigh.
• No scripting or user JavaScript. KyBook's power-user scripting has no equivalent. This is niche, but if you built workflows on it, they will not carry over.

If any of these is central to how you read, be honest with yourself about it now. A clean migration that you planned for beats discovering the gap a week after you deleted KyBook.

The price question, head-on

The obvious objection: KyBook was a roughly $3.99 one-time purchase, and justRead is a subscription. That deserves a straight answer, not a dodge.

justRead runs a 14-day free trial, then $2.99 per month, $24.99 per year, or a $59 one-time lifetime purchase. So if a subscription is the sticking point, the lifetime tier is the like-for-like comparison, and here is the honest frame. KyBook's one-time price bought you an app that has now been frozen since 2019, with a core feature (its OPDS and Calibre networking) actively breaking on new iOS and no one to fix it. justRead's lifetime tier is also pay-once, but for an app that is still shipping updates and still connecting. You are not choosing between paying and not paying. You are choosing between paying once for something frozen and paying once for something maintained. The trial exists precisely so you can confirm your OPDS servers, your Calibre library, and your fonts all come across before you spend anything.

Other realistic alternatives

justRead is not the only option, and depending on what your KyBook library actually held, another app may fit you better. I would rather you land on the right reader than on mine.

• Yomu is a real contender for Calibre and OPDS users and worth a look. Its one hard limitation for former KyBook users: it cannot load custom fonts. If bringing your own typefaces was part of why you used KyBook, that is likely disqualifying, but if it was not, Yomu is a reasonable pick.
• PocketBook Reader is free and handles a broad range of formats, which makes it a sensible landing spot if format breadth is your priority and you do not want to convert files. It is a genuine alternative for mixed collections.
• Panels and Chunky are the answer for comics and manga in CBR/CBZ, which no general EPUB reader (justRead included) will handle. Pair one of these with your text reader rather than looking for a single app that does both well.
• KOReader is the power-user's power tool, but on iOS it requires sideloading and a tolerance for tinkering. If you are the kind of KyBook user who lived in advanced settings and does not mind the setup, it is worth knowing about. If you want something that just installs from the App Store, it is not for you.
• Apple Books is free and built in, but it has no OPDS, no self-hosted access, and minimal typography control. For a former KyBook user that is a downgrade on every axis you cared about. Fine as a casual second reader, not a replacement.
• Marvin 3 comes up constantly in these threads, and it is a cautionary tale, not an option: it was pulled from the App Store around early 2024 and is itself abandoned. Migrating from one dead reader to another just resets this same clock. We cover its status in Marvin 3 in 2026: still working? and the Marvin 3 alternative comparison.
• Moon+ Reader gets recommended reflexively, but it is Android only. There is no iPhone or iPad version, so it is a non-starter on iOS no matter how often you see it suggested.

If you want a wider survey of the field without the KyBook framing, the best EPUB reader apps for iPhone and iPad roundup compares the current readers head to head.

How to migrate off KyBook 3, step by step

Moving over is mostly a normal file handoff plus reconnecting your servers. There is no special importer between the apps, and that is fine, because if your library is managed properly, KyBook was never the master copy anyway. Do this while KyBook still launches.

1. Find your master files. If your books live in Calibre or a cloud folder, that is your source of truth and you can skip exporting from KyBook entirely. If some books exist only inside KyBook, use its export or share options to get those EPUBs out to the Files app now, before any iOS update can lock you out.
2. Convert anything that is not EPUB or PDF. Run FB2, DJVU, MOBI, and AZW3 files through Calibre to produce EPUBs. Calibre does FB2 to EPUB cleanly in bulk, and handles the Kindle formats too. Do this before you uninstall anything so you are not stranded.
3. Reconnect your OPDS servers. In justRead, re-add each catalog by URL. This is usually the fastest part, since you are just re-entering addresses you already know. Gutenberg and the Internet Archive are already built in.
4. Connect Calibre over Wi-Fi. If you ran a Calibre setup, start the Content Server on your computer and let justRead discover it on the network, or enter it manually, then pull your library. From here progress, ratings, and finish dates sync back to Calibre automatically.
5. Import your loose files. For one-off EPUBs and PDFs sitting in Files, iCloud, Dropbox, Google Drive, or OneDrive, open them into justRead or point it at the folder to read in place. On iPad you can also drag and drop files straight into the app.
6. Confirm, then delete. Open several books, check your catalogs connect and positions look right, and only then remove KyBook. Do not delete it until you have verified nothing was left behind, especially any books that lived only inside it.

If you hate duplicating files, lean on the cloud-folder approach in step 5: point justRead at a folder in iCloud, Dropbox, Google Drive, or OneDrive and read from there, keeping a single copy of each book instead of importing everything into app storage.

FAQ

What happened to KyBook 3?

Its last update was version 0.7.8 in February 2019, so it has gone more than seven years without maintenance. It still installs and launches on many devices (iOS 11 and up, 64-bit) and still holds a strong App Store rating from its active years, but it receives no fixes. Notably, its OPDS and Calibre connections have been reported breaking on newer iOS while the older KyBook 2 kept working, which is a documented regression in the exact feature power users relied on.

Does justRead support OPDS the way KyBook did?

Yes, and its OPDS still connects in 2026. You add catalogs by URL, browse and search them in the app with server-side search and category browsing, and download into your library. Project Gutenberg and the Internet Archive are built in, and custom servers including Calibre's OPDS feed, calibre-web, Kavita, Komga, and COPS are supported. For self-hosted setups it also offers a two-way Calibre Content Server connection that goes beyond a plain OPDS download.

Can justRead read FB2, DJVU, MOBI, or AZW3 files?

No. justRead reads EPUB and PDF only, and PDF is read-only. This is the main thing KyBook did that justRead does not. Convert those files to EPUB in Calibre first (it handles FB2, MOBI, and AZW3 cleanly, including bulk), or keep a separate app for the stragglers.

What about my comics in CBR and CBZ?

justRead does not read comic formats. Use a dedicated comic reader such as Panels or Chunky for CBR and CBZ, and use justRead for your reflowable EPUBs and PDFs. This is a companion setup, not a single-app replacement, if comics are a real part of your library.

Does justRead have text-to-speech like KyBook?

No. justRead does not synthesize speech from a plain EPUB. It does play actual audiobook files, with speed control, chapters, and a sleep timer, and it supports read-along narration for EPUB3 books with media overlays, but that is separate from TTS. If you specifically relied on KyBook's text-to-speech, that is a genuine gap to weigh.

Does justRead sync with Calibre?

Yes, with two-way Calibre Content Server sync. It discovers your server over Wi-Fi (or you enter it manually), shows New, Changed, and Synced badges so you pull only what changed, and writes reading progress, ratings, finish dates, and stats back to Calibre. It supports multiple libraries and HTTP Digest authentication, and syncs PDFs alongside EPUBs. This is a step beyond KyBook's one-way OPDS download.

Does justRead read from Dropbox or Google Drive?

Yes. It syncs across your own devices via iCloud, and you can point it at any reachable cloud folder including Dropbox, Google Drive, and OneDrive to read in place. Calibre Content Server sync and OPDS catalogs are additional ways to get books in.

Will my reading progress and highlights carry over from KyBook?

Not automatically. There is no direct import path between the apps. If your library is managed in Calibre, sync from there and your progress lives with the server going forward. For loose files you import the EPUBs and start fresh on reading position. Export any KyBook highlights you want to keep before you delete the app.

Does justRead play audiobooks?

Yes. It has a built-in audiobook player with variable speed, chapter navigation, and a sleep timer, plus read-along narration for EPUB3 books that include media overlays, so the text highlights in sync with the audio. For former KyBook users who used it as an audio player, this is a real parity point.

Is justRead worth a subscription when KyBook was a one-time purchase?

That is a fair question. justRead offers a 14-day free trial, then $2.99 per month, $24.99 per year, or a $59 one-time lifetime purchase. The like-for-like comparison is lifetime versus KyBook's roughly $4 one-time price. The honest difference: KyBook's one-time price bought an app now frozen since 2019 with features actively breaking, while justRead's lifetime tier is pay-once for an app still shipping updates. Use the trial to confirm your servers, library, and fonts come across before paying anything.

Picking a reader you can keep

The hard part of replacing KyBook is not finding an app that opens an EPUB, plenty do. It is finding one that keeps your OPDS catalogs and self-hosted library working and will still be updated a year from now. That second condition is the one KyBook stopped meeting in 2019, and it is why the app is quietly breaking on you today.

If OPDS, self-hosted Calibre, custom fonts, and deep typography were the reasons you stuck with KyBook, justRead covers all four on iPhone and iPad, with two-way Calibre sync, ZIP font import, built-in Gutenberg and Internet Archive, per-book settings, audiobook playback, and highlight export. Just go in knowing it is EPUB and PDF only with no comics or TTS, and convert or offload anything else before you switch.

To go deeper, see how the OPDS reader handles custom catalogs, walk through the Calibre sync setup, or compare the wider field in the best EPUB reader apps for iPhone and iPad roundup. When you are ready, download justRead on the App Store and rebuild your library on a reader that will still be here next year.