10 ms·

Your ePub Is fine

919 points by sohkamyung 4mo ago

anenefan 4mo ago
The TLDR version is Abode supports backward compatibility ... and epub - * International Digital Publishing Forum* - is playing with a sprawling mess opting for the race to the top newest standards ... that always works so well and ensures the user base is always upgrading. I'm very grateful for this information and it explains why I've avoided epub opting for pdf over epub as my reader software is old. I'm am very much on the side of supporting backwards compatibility. It reminds me of the times the M$ used to upgrade their doc standards ... where if one hadn't upgraded, well bad luck.
- simcop2387 4mo ago
  I think its one reason ive been happy with software based epub readers where upgrading is usually reasonable to do. Either on my phone or android based eink reader. That said if they change too much then yea nobody will produce the new standard and only support the old one if it isnt carefully designed for graceful degredation.
- MrLeap 4mo ago
  An epub is just a plain html webpage compressed into a zip and its extension changed from .zip to ".epub". Assuming you have a web browser, you have something that will almost certainly render your epubs contents. PDF is not nearly as pleasant under the hood. It's down right lovecraftian.
  - ablob 4mo ago
    The lovecraftian horror of pdf mostly comes into play through the sheer amount of software that supply almost correct pdf. It's not enough to be able to read pdf anymore, you also have to be able to deal with software that emits subtly wrong documents.
    - PunchyHamster 4mo ago
      Adobe really have perfected act of making the most shoddy software that is still possible to sell
      - m463 4mo ago
        I'm reminded of "PSD is not my favourite file format." https://b3n.org/psd-is-not-my-favourite-file-format/ https://b3n.org/psd-is-not-my-favourite-file-format/ or in the code: https://github.com/gco/xee/blob/master/XeePhotoshopLoader.m https://github.com/gco/xee/blob/master/XeePhotoshopLoader.m
    - rcxdude 4mo ago
      That's part of it, but the design of PDF really doesn't help
  - goodmythical 4mo ago
    I was floored to discover this recently when I clicked "edit" in calibre for the first time a few weeks ago. Straight HTML, edit anything everywhere. Super slick.
  - anenefan 4mo ago
    I'm aware thanks. Mostly it's just my preferred viewer is older than css4 but it's been nice to find out why that was the case. PDFs can be painful as well, more often it's then using abode's pdf viewer, but it's far less common for me. There was a time many years ago when I understood PDF structures better, back when I chose to manually edit and fix a couple of malformed PDFs.
- gsnedders 4mo ago
  To be clear, ADE’s behaviour is not conforming to any version of the standards it claims to implement. If it had been, it would reject that specific max-width property declaration as having an invalid value and ignore it, not reject the entire document: every single version of CSS has required that forwards-compatible behaviour. PDF is not somehow immune to this either — a non-conforming implementation could similarly break what are meant to be forward-compatible extension points by raising an error on an unknown stream or object instead of (as required by the standard) ignoring it.
  - anenefan 4mo ago
    So if I understand correctly a struggling epub viewer or ADE should skip css that it considers malformed - which means the reason my viewers have considered a epub to be not able to be viewed / corrupt / whatever it is for some other reason than more recent / current css implementation. PDFs certainly can suck, more often those that will only work with abode's software and other viewers I've tried can not.
    - gsnedders 4mo ago
      While plausible, I would suspect it’s more likely you’ve just run into bugs than forwards-compatible error behaviour — most ePubs don’t get anywhere near actually interesting CSS!
L-four 4mo ago
It's always CSS.
- m463 4mo ago
  compatible style stuff
charcircuit 4mo ago
>but it can’t validate CSS against a renderer which is fundamentally broken! The epub standard doesn't say what version of CSS must be supported. There were no guarantees modern CSS would work so I wouldn't call the renderer broken.
- ninth_ant 4mo ago
  If the renderer completely fails because of a minor issue when parsing the css, that is broken.
- nightpool 4mo ago
  No, the CSS spec is specifically designed to be forwards compatible because of exactly this issue. Any invalid CSS rule should only cause that specific line to be ignored, not the whole stylesheet. And certainly even if your CSS parser chokes in some specific case, it shouldn't cause your ereader to fail to load the entire book!
- gsnedders 4mo ago
  You are of course correct that ePub nowadays doesn’t mandate a given version of CSS (though earlier versions did!), but that doesn’t matter in this case: it’s non-conforming according to even CSS level 1 (1996), per https://www.w3.org/TR/REC-CSS1-961217#forward-compatible-parsing https://www.w3.org/TR/REC-CSS1-961217#forward-compatible-par... > illegal values, or values with illegal parts, are treated as if the declaration weren't there at all So a conforming implementation would ignore that max-width property declaration, not raise an error. And those earlier versions of ePub which defined a required subset of given CSS standards? The forwards-compatible parsing rules were part of their subset.
- acdha 4mo ago
  The parser is broken. The CSS standard says that parsers MUST ignore properties they don't recognize.
- Ardren 4mo ago
  ePub3 is CSS2.1 (+ some extras) CSS21 standard says "Illegal values. User agents must ignore a declaration with an illegal value." Ignore != Fatal error
tech234a 4mo ago
Adobe Digital Editions and RMSDK were recently sold to Wipro Engineering: https://helpx.adobe.com/enterprise/kb/eol-faq-adobe-digital-editions.html https://helpx.adobe.com/enterprise/kb/eol-faq-adobe-digital-...
- thisislife2 4mo ago
  Sold or outsourced?
  - Finnucane 4mo ago
    'transitioned'
  - wut42 4mo ago
    > Wipro now manages and distributes any new updates, enhancements, bug fixes, and support requests directly > Create your new ByteBooks ID using the same email address that you used for Adobe ID Seems sold mostly.
jwrallie 4mo ago
> When I started out, I dreaded the moment when I hit the validate button on my finished book after months of work, because it would always find something to cry about. I remembered one particular master student on the verge of tears trying to compile his LaTeX thesis draft, he took the “write and think about formatting later” too literally and was trying to compile it for the first time very close to the deadline.
- gnatolf 4mo ago
  Which, to be fair, overall probably still saved quite some time. The compile times alone would've meant they wasted so much more time by repeated earlier checks. Whether a looming deadline changed the perception about that, we don't know ;-P
- samtheDamned 4mo ago
  This is similar to my experience doing a research project for a fellowship. I had a barebones LaTeX file but I pushed doing the proper formatting for when I was finished writing and then had a hell of a time trying to get it all working properly right before the submission date haha.
tannhaeuser 4mo ago
Unfortunately, epub and epubcheck isn't the great uncontroversial resource the author makes it out to be. When W3C, Inc. took over maintenance of the EPub spec around when 3.1 was current, they just referenced WHATWG HTML and other ever-expanding browser specs ([1]). Being "living standards", these have no versioning or QA. As a consequence of being based on a version of HTML that redefined headers and sectioning, Epub 3.2 just made existing epubs non-conforming. Which is why Calibre and other tool still recommend 3.1 or better yet 2. The case mentioned where the CSS min() function is rejected is another place where bulk import of the extremely complex CSS spec is just not helpful. Ebook readers aren't evergreen browsers after all. [1]: https://news.ycombinator.com/item?id=41326179 https://news.ycombinator.com/item?id=41326179
- ramblurr 4mo ago
  Yes, it is widely known in the epub space that targeting 3.1 or 2 is the more sane option. With EPUB compatibility issues CSS should always be suspect number 1. Using "modern" CSS features and complaining about missing flex boxz grid, etc is a web developer's mindset. Just because EPUB shares some of the stack with the web doesn't mean they perfectly overlap (or even should). Hardly any e-ink embedded e-reader devices use a browser for rendering, they all use purpose built HTML/CSS parsing and rendering toolchains, are baked into firmware and updated once in a blue moon. (If you're interested look at koreader's crengine or Crosspoint reader which runs on an ESP32!) The blog post reeks of overly confident AI prose. But don't be fooled.
  - lavela 4mo ago
    Shouldn't a CSS engine just ignore directives it doesn't know? At least it shouldn't fail without an error.
    - jiehong 4mo ago
      Came here to say exactly that: CSS was designed to be friendly and just ignore any line it doesn’t understand. It’s the whole point of browsers and progressive improvements.
lidavidm 4mo ago
AIUI, Kobo devices have a more advanced rendering engine if you name the file with .kepub.epub. (I think it's based on ePub 3?) Not sure if it would fix the problem here. But I personally run ePubs through kepubify (https://pgaskin.net/kepubify/try/ https://pgaskin.net/kepubify/try/) before transferring them to my Kobo.
- louisbourgault 4mo ago
  Yes, I do that for everything too. Also publishers like Standard ebooks provide a kepub download - as they explain here they have problems with the Adobe reader too. https://standardebooks.org/help/how-to-use-our-ebooks#kobo-faq https://standardebooks.org/help/how-to-use-our-ebooks#kobo-f... I love my Kobo (clara colour) and really, if they just removed the Adobe reader, it'd be perfect. And yes, I've tried KOreader, but never switched to it because I like my Overdrive library books and Kobo Store.
  - buu709 4mo ago
    > I love my Kobo (clara colour) and really, if they just removed the Adobe reader, it'd be perfect. And yes, I've tried KOreader, but never switched to it because I like my Overdrive library books and Kobo Store. You may have already tried this, but they all work fine together. You can just exit the KOReader app and use the default Kobo stuff, then open KOReader again when you want to read something via that.
- FinnKuhn 4mo ago
  Looks like this info was added to the post as an update.
acdha 4mo ago
Adobe has always been like this, too. They squandered an enormous marketshare with Flash because the alternative would've been spending a couple million on QA and they managed to unite all of the browser manufacturers in agreement that the web was better off without such an unreliable partner. I shipped a couple of things on Flash back in the day but it was staggeringly bad software — random crashes, various heisenbugs where changes in one area would affect unrelated functionality in other modules, etc. — and while it cost something like $800, it was completely unsupported: I filed a number of trivially reproducible bugs with reduced test cases but never heard anything back until the next release came out and they sent automated suggestions that the bug might be fixed so I should buy a full-price license and find out.
- echelon 4mo ago
  Flash is still unsurpassed as the easiest publishing medium. JavaScript build system layer cake and "web standards" are a million times harder than just drawing some stuff, maybe writing a simple function, then building a static file that can be embedded anywhere and even downloaded. You have to spend so much time setting up any flash alternative, and the "standards" are worse. I hate Steve Jobs for killing Flash and Adobe for being such awful stewards of one of the most amazing web technologies. Kids growing up today have no idea how magical Flash was. It was like Roblox or Minecraft for web. Websites are still inferior to Flash of the early 2000s. It's taken decades and they can only mimic a fraction of its power. And none of its ease.
  - LeFantome 4mo ago
    You know you can use Ruffle if you really want Flash right? https://ruffle.rs https://ruffle.rs But the only standard you need is WASM. All browsers support it. Use whatever you want to make it. In fact, Ruffle is just a WASM app.
    - ameliaquining 4mo ago
      The problem is that, while there's no theoretical barrier to an authoring tool with a Director-like user experience that exports to Wasm, no one has actually written one, and it's not a small amount of work. (I agree that we're better off without Flash, but this particular problem is real and unsolved.)
TeaVMFan 4mo ago
When building EPublish ( https://frequal.com/epublish/ https://frequal.com/epublish/ ), an HTML-to-epub converter, I faced similar hurdles. Trying to keep compatibility with numerous e-readers built with different stacks and varying degrees of EPUB versions is frustrating. I used EPublish for my first novel, Means and Motive, just published here, DRM-free: https://www.amazon.com/dp/B0GYCZJVGX https://www.amazon.com/dp/B0GYCZJVGX So far I haven't heard of compatibility issues, so I think EPublish has hit the sweet spot of EPUB targeting. I agree, however, that it feels like the old days of targeting IE6 on the web. Old readers still exist out there, so we have to aim for the lowest common denominator.
badsectoracula 4mo ago
Be happy your readers use an ePub reader that supports (or at least, ignores) something like `max-width` in the first place :-P. TBH i've being using an ePub reader that i occasionally had to edit ePub files so i get rid of the superfluous styling that made it either not work or show things weirdly/wrong and i've heard comments from others that a bunch of files i had no issues with personally were unreadable for them, which makes me think that unless you really and absolutely need any fancy formatting (i.e. math stuff that can't just be made images - and you really tried to!) then you should stick with the most basic HTML imaginable - things that not even IE4 would render (too) wrong. And in turn, since i doubt this will ever happen, i sometimes ponder making an "epub reconstruct" tool that attempts to reconstruct epubs so that they use the simplest HTML/CSS :-P (ideally configurable for maximum compatibility).
- thatguy00 4mo ago
  Ah, yes. When I paint, I also leave the middle unpainted, in case some people have a crack in their glasses that would make the painting look weird. Or maybe we should tell glasses makers to make better glasses and let the artists make their art.
  - teddyh 4mo ago
    People making shows for TV had to respect the TV ”safe area”: <https://en.wikipedia.org/w/index.php?title=Safe_area_(television)&oldid=1289553744 https://en.wikipedia.org/w/index.php?title=Safe_area_(televi...>
- dlcarrier 4mo ago
  It's already bad enough that HTML/CSS barely works in the target web browser environment, I don't see why anyone decided it was a good idea to use it for books. I've often thought about figuring out a subset that operates fast on any computer and sticking to that for any web pages I make. If someone figured that out for epub, it would make it much, much more useful.
WolfeReader 4mo ago
Every Kobo reader is capable of running KoReader ( http://koreader.rocks/ http://koreader.rocks/ ). That's the first, and probably last, step I'd take to render a book that the default reader takes issue with.
- criddell 4mo ago
  As I understand it, KoReader doesn’t work with drm protected books which means I can’t use it with most books I buy. Ebook producers really should be forced to either drop drm or adopt a cross-platform standard.
  - downsplat 4mo ago
    Search around, there's surely a way to break the drm. When theres no better way that's what I do too: pay for the book, convert to plain epub. The publishing industry never got its head out of... some dark place. We've been able to buy mp3s without drm for ages, but somehow books are different.
    - sync 4mo ago
      If you have a ACSM (the file type Adobe Digital Editions uses for DRM) I’ve been using https://www.acsm-converter.com https://www.acsm-converter.com to strip the DRM and return a standard epub
  - troyvit 4mo ago
    It's probably too annoying for most, but I had a similar problem with KoReader and library books because those too depend on DRM. I ended up keeping KoReader as an app, then just not loading the app when I was reading a library book. It wasn't too bad. KoReader also gave me a lot of freedom to manage the bad battery life of my Kobo Sage before it died of other causes. Definitely worth the extra cognitive load of dealing with the two experiences.
Javalicious 4mo ago
Wow. This brings up some (bad) memories of working with an .epub export about 10 years ago. We had some embedded fonts to work around some poor rendering in some of the readers we tested, but some of the readers ignored the fonts altogether, causing the content to render boxes (bangs head on table) It looks like not a whole lot has changed in that space -- the readers are still the gate for what you can do with the format. Who's available to make a CanIUse for epub readers, to shame them into compliance? (only partly /s)
nfw2 4mo ago
As someone who has spent a good deal of time trying to build ereader software, eventually I decided to try to deal with the devil and build on top of RMSDK. There is no way to get access to it. I don't mean the licensing cost is prohibitively expensive for an indie dev although I understand that to be the case as well. There is no one to talk to. The email listed on their website does not respond to anything. Not even so much as a "Thanks for your interest" or a "We will get back to you". I messaged a former colleague who worked there to try to see what the process is to get access to rmsdk. He said he tried to find internal docs about it and couldn't find anything. I tried to find people on linkedin who might be associated with rmsdk and ask them and similarly found nothing. Meanwhile publishers only distribute most of their titles with one of their known drm vendors ie Apple, Amazon, or Adobe. The other two are entirely closed off. If this isn't anticompetitive trust behavior, I don't know what is.
- stonecharioteer 4mo ago
  Hello, I'm building https://merrilin.ai https://merrilin.ai, could I pick your brain about the problems you faced?
  - nfw2 4mo ago
    Sure thing. I've actually been working on the spoiler-free resource angle as well. I can book a call to talk. Distribution is the killer problem here though.
    - sanex 4mo ago
      I thought about building this too! Love that both of you are pursuing it as I haven't had the time to start. Don't give up.
      - stonecharioteer 4mo ago
        Yay! Registrations to https://merrilin.ai https://merrilin.ai are open and you can enjoy a free account for as long as I can afford to give it (I have no funding lol). The android app is ready for closed testing too, if you have an Android device, mail me at mail [at] stonecharioteer.com and I'll add you to the beta testing. ios is still a pain.
naikrovek 4mo ago
Death to Adobe. For this reason and 10,000 others.
danpalmer 4mo ago
> Epubcheck does basic CSS checking of course, but it can’t validate CSS against a renderer which is fundamentally broken! But isn't that kind of the point of epubcheck? It's surely not intended to validate all of CSS, it's intended to validate that an epub will work... and not working on Kobo devices (probably #2 manufacturer of ebook readers?) is a major issue.
- gsnedders 4mo ago
  epubcheck is meant to ensure conformance with the standards, not the interoperably implemented subset of the standards. (Which has lots of awkward questions: which implementations of the standards, which versions of those implementations, etc.)
  - ameliaquining 4mo ago
    The latter seems like what the tool's users actually want. That it's a harder problem doesn't change that.
    - MadnessASAP 4mo ago
      The user wants the website to work in IE6, developing and testing only against IE6 to the detriment of other browsers is not generally regarded as a healthy state of affairs. The standard exists, it is the responsibility of both the producer and consumer of ePUB files to adhere to the standard. https://en.wikipedia.org/wiki/Robustness_principle https://en.wikipedia.org/wiki/Robustness_principle
      - ameliaquining 4mo ago
        If a large fraction of your users are on IE6 and you can't realistically get them off it, you need to make sure your site works in IE6, and good tooling should help you do this. Of course you also want to make sure it works in other browsers your users use, and a standard may be helpful in doing that.
    - 4mo ago
chocolatkey 4mo ago
Kobo is actually in the process of completely rewriting their e-reader software (you can download the beta in the EU), and I’m pretty sure it’s no longer based on RMSDK. Adobe basically handed the EPUB DRM market to LCP on a silver platter by being a poor maintainer and then selling off to a third party that had botched the migration and further angered end users and platforms, that are switching off Adobe faster than ever
- el_benhameen 4mo ago
  Have you tried the beta? Have you found it to be substantially better?
  - chocolatkey 4mo ago
    I’m not in the EU so I have not, this is based on the technical changes mentioned, and what I’ve heard from people. Feel free to try if you are in the EU: kobo.com/update
- anilakar 4mo ago
  Only in EU because of the Accessibility Act[1]. Copywrong holders are allowed to disable screen readers elsewhere because that allows them to sell more audiobooks. You will apparently also lose many other features, among them Asian scripts and developer mode. [1] https://www.kobo.com/kobo-writing-life/blog/our-commitment-to-accessibility-and-the-european-accessibility-act-eaa https://www.kobo.com/kobo-writing-life/blog/our-commitment-t...
- BoingBoomTschak 4mo ago
  Interesting news! Though I'm on https://koreader.rocks/ https://koreader.rocks/ like most people here, I suppose.
dottchen 4mo ago
BOOX works fine. One solution is to ask Codex to reformat your epub file before importing it to your ereader.
- tcoff91 4mo ago
  I love my Boox, I run Storyteller on it instead of the native e-reader. I love that it’s just an android tablet with an e-ink screen.
- yoavm 4mo ago
  BOOX devices are great except for the GPL violation. It's really a shame.
boznz 4mo ago
For my free novels which I deliberately keep the styles to header2 and body text, it is surprising the amount of crud that all the ePub conversion softwares generate, especially since they are just zipped web-pages. These days I usually get 90% of the way on google docs, then do the final editing on LibreOffice which can add things like tables of contents and cover image, if it opens on Kindle, Kobo and Calibre I consider it job done.
GreenSalem 4mo ago
"EPUB is an amazing open standard for ebooks, and yet so many implementations of it are just fundamentally flawed, all in the name of keeping IP lawyers happy." Easy to be dismissive, but IP violations can cost a large company hundreds of millions. IP lawyers are more important to many companies than their software developers. If you doubt that, check to see who gets paid more...
unnouinceput 4mo ago
I don't like .epub. I understand the reasons why this format exists, and I am 100% behind those reasons. But it's because I don't find any EPUB readers appealing to me. Just give me a FoxIt Reader clone for .epub, that's all. But naaaah!!, every single fucking e-pub reader that I tried must be a fucking library collector instead, like it's 2000's Windows Media Player style. I hate that. As such, whenever I get my hands on an .epub file, I go to an online converter, convert it to a .pdf file and nuke it from my system. Then the .pdf gets opened in my FoxIt.
- __float 4mo ago
  Hmm, Sumatra PDF perhaps?
- pteraspidomorph 4mo ago
  Have you tried foliate? Their embedded reader works quite well for me.
- stonecharioteer 4mo ago
  As someone who loves FoxIt reader, I'm building https://merrilin.ai https://merrilin.ai to be the best damned ebook reader out there, to support PDF and epub. FoxIt's annotation system is one of the best I've experienced and I want to design one that is just as good if not better.
  - gabrieletrovato 4mo ago
    Building a robust annotation system for both PDF and EPUB is a tough technical challenge, but definitely needed. I've been working in a similar space and recently open-sourced it. It's a local-first 3D library for organizing and reading EPUBs and PDFs directly in the browser. It's called KoreShelf on Github
    - majora2007 4mo ago
      I just released a pretty solid annotation system for Kavita's EPUB reader. It wasn't super challenging (although Kavita has a custom epub renderer). Now doing that with PDF would actually make it challenging. Annotation system (with pics): https://wiki.kavitareader.com/guides/readers/epub/#annotationshighlights https://wiki.kavitareader.com/guides/readers/epub/#annotatio...
hardwaresofton 4mo ago
BTW for those who are looking for a device, the PineNote exists: https://pine64.org/devices/pinenote/ https://pine64.org/devices/pinenote/ More expensive and less out-of-the-box software, but straight to the point on device ownership/what kind of software you can run, fewer strings attached. [EDIT] Great experience blogs on the PineNote https://shom.dev/posts/20250308_pinenote-day-one/ https://shom.dev/posts/20250308_pinenote-day-one/ https://shom.dev/posts/20250406_a-pinenote-only-5-day-weekend/ https://shom.dev/posts/20250406_a-pinenote-only-5-day-weeken...
- ndiddy 4mo ago
  Have you tried the PineNote yourself? It $400 and says that it's "aimed at Linux developers with an extensive knowledge of embedded systems and/or experience with mobile Linux." The community provided firmware they link for it hasn't been updated in over a year. The Kobos don't limit what you can do with them either, you can sideload alternative e-reader software like KOReader that improves on the built-in reader functionality.
  - hardwaresofton 4mo ago
    > More expensive and less out-of-the-box software, but straight to the point on device ownership/what kind of software you can run, fewer strings attached. This note was in the original comment, did you read it? The fact that it is $400 (more expensive) and has less out of the box software is literally mentioned to alert people to that. > The Kobos don't limit what you can do with them either, you can sideload alternative e-reader software like KOReader that improves on the built-in reader functionality. This is patently false, the latest Kobo Libra Color is using secure boot which completely locks out custom development: https://www.mobileread.com/forums/showthread.php?t=363175 https://www.mobileread.com/forums/showthread.php?t=363175 So much so that QuillOS which used to be Kobo focused rewrote to support the PineNote https://github.com/Quill-OS/quill https://github.com/Quill-OS/quill https://quill-os.org/ https://quill-os.org/ The point is to buy hardware that is built for you to freely modify and fully own, from the start. My post was to make sure everyone knew the PineNote was an option, because I certainly did not know it until someone on HN made me aware. Could you maybe make your point more concrete? Are you attempting to completely dissuade people from using the PineNote because it may not be easy to side load apps to it on hacker news?. Obviously different people have different propensities to do hacking, and some may not be able to afford the PineNote due to how expensive it is, but it's not clear what the goal of your comment was. If your goal was "invest in Kobo instead of PineNote", I disagree with that. I'm not interested in investing (whether money or time) in an ecosystem that is just going to rug pull me eventually, over nickels and dimes. BTW for those who agree, another great option is XTeink -- very hackable, and I've bought one myself: https://www.xteink.com/ https://www.xteink.com/ And there's a Linux phone out there which looks pretty encouraging too: https://furilabs.com/shop/flx1splus/ https://furilabs.com/shop/flx1splus/ Graphene is likely still the easier more polished option, but it's great to have options these days.
gcanyon 4mo ago
Is there a way to root the kobo and put a modern renderer in place?
- MadnessASAP 4mo ago
  Yes, for the ones I've owned rooting is very easy. KOReader and Plato are both popular (amongst the community of eReader rooting people) alternatives to the OEM software.
- t-3 4mo ago
  It runs a standard linux and mounts as external storage when connected over USB. No need to "root" at all.
- WorldMaker 4mo ago
  The article's update points out that it switches to a modern renderer if you rename .epub to .kepub.epub, which seems like a dumb way to handle that rather than a DRM existence/version check, but that's not entirely unusual for backwards compatibility support shenanigans. (Others point out that Calibre automatically will rename epub files to .kepub.epub for you if you use it to manage a Kobo library. It's just manually copying files to Kobo where you need to remember to do it yourself if you have a Kobo.)
itsthecourier 4mo ago
bro, what an anchor to the past that framework is
BonoboIO 4mo ago
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Edwingg 4mo ago
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Edwingg 4mo ago
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k_sze 4mo ago
The author says that "In a perfect world, RMSDK would just stop living in the CSS stone-ages or at least provide some kind of error handling instead of dropping the whole book, but I’m not holding my breath." This is blatantly wrong. In a perfect world, RMSDK wouldn't exist in the first place and Adobe would have gone bankrupt and become history at least 10 years ago.
- m463 4mo ago
  Actually - in a perfect world steve jobs would have written a missive about it and killed it from orbit. https://en.wikipedia.org/wiki/Thoughts_on_Flash https://en.wikipedia.org/wiki/Thoughts_on_Flash https://web.archive.org/web/20170615060422/https://www.apple.com/hotnews/thoughts-on-flash/ https://web.archive.org/web/20170615060422/https://www.apple...
mannyv 4mo ago
"Epubcheck does basic CSS checking of course, but it can’t validate CSS against a renderer which is fundamentally broken!" According to the author, Kobo uses CSS from 2013. A quick check with an AI says RMSDK supports CSS 2.1 and parts of 3. So it's not that the renderer is broken, it's that he believed that epubcheck actually checks against devices and the versions of CSS that those devices support. This is exactly the issue with test tools: the test tool tests to a spec, but the platform is the gold standard. If you don't like it tough shit.
- WorldMaker 4mo ago
  The CSS 1 spec says to robustly ignore lines you don't understand. Adobe didn't need to predict CSS 4, they needed to better implement CSS 1.
pmontra 4mo ago
I understand the frustration of the author but how many readers do have an old, unupgraded, maybe unupgradable epub reader? If authors want to make their work available to all readers they have to build for the least common denominator. If it happens to be something from 2013, sorry but that's the reality of the market.
- graeme 4mo ago
  I read this as saying a new Kobo in 2026 uses Adobe drm software that has css rules stuck in 2013.
- qubidt 4mo ago
  The issue the author is explaining is relevant for the Kobo devices currently being sold
protocolture 4mo ago
I once read an ebook that was formatted by a guy who had only ever done magazines and it was a huge mess. 2 columns of text per page. No auto scaling. The best ebook format I have ever experienced is .txt and just let the software figure out where the text needs to go.
- microflash 4mo ago
  Many ePub readers allow you to ignore formatting. And that’s exactly what I do.
- TiredOfLife 4mo ago
  The best format was fb2
  - Self-Perfection 4mo ago
    Why "was"? I still read books in fb2.
nanapipirara 4mo ago
I’m supposed to be able to lend ebooks from my local library. Adobe makes it impossible as their software doesn’t run on my macbook…
- themadturk 4mo ago
  Adobe Digital Editions runs on my MacBook Air M3 with macOS Tahoe. What problem do you see? (FWIW, ADE will probably die when Rosetta support goes away with MacOS 28, but one of the de-DRM plugins will read acsm files directly and bring in the books.)
insumanth 4mo ago
> that bloated pinnacle of software that is 80% about DRM, 20% about the reading experience I have never seen someone explain the adobe software so perfectly. Using any adobe software is exactly this.
- matwood 4mo ago
  Unfortunately this is any reader software that deals with publishers who require DRM. IME, the vast majority of bugs also come from the DRM.
latexr 4mo ago
I’m curious if simply running the original EPUB through Kepubify fixes the problem. https://pgaskin.net/kepubify/ https://pgaskin.net/kepubify/
bowsamic 4mo ago
ePub compatibility issues are one of the worst parts of having a Kobo reader. I genuinely miss my Kindle and its simple but reliable MOBI format. At least there everything worked
- ornornor 4mo ago
  I don’t miss my kindle, at all. Its text layout engine was a joke (every page edge was ragged!), you depend very heavily on amazons goodwill to keep allowing you, the device owner, to sideload your own books, it’s getting harder to install third party software, and well that one is personal but it’s from Amazon. I’ve switched to kobos (Clara HD) and I’ve had to for years. It’s chugging along (had to 3d print a replacement power button a couple months ago), I can run koreader no problem and use calibre with the kobo plugin. And the default rendering engine in kobo’s firmware does actually typeset the text: no ragged edges!
ceving 4mo ago
If nobody is able to implement the standard it is probably not amazing.
ornornor 4mo ago
If you use a kobo you have to give koreader a whirl! The only thing missing for me is the unified view of the library: koreader requires you to navigate to the subdirectory to open your ebook whereas nickel (kobo’s UI) will list them all in one library regardless of how deeply nested they are. Everything else is better with koreader and it’s super easy to install alongside nickel. And it works very well with calibre + the kobo plugin.
- martin- 4mo ago
  There are several plugins that give you a library view based on metadata instead of folders and filenames. Two examples that are both great: https://github.com/AndyHazz/bookshelf.koplugin https://github.com/AndyHazz/bookshelf.koplugin https://github.com/joshuacant/ProjectTitle https://github.com/joshuacant/ProjectTitle
  - ornornor 4mo ago
    Thanks, I had no idea, these look great!
- themadturk 4mo ago
  You can also play with Calibre's default transfer template so all book files go into a single folder of your choice on the device. Then you can set your KOReader home or favorites folder and see everything in one place.
icantevenhold 4mo ago
I recently was in the market for a new e-reader and steered away from Kobo and Kindle because of their non-free ecosystem. I don’t know how exactly it would negatively impact me but I didn’t want to find out. Got a refurbished pocketbook in the end and very happy with it, it reads all imaginable file formats and I can just send books to it via email or cable.
- dakolli 4mo ago
  I don't really have an issue with kindle, I just download anything off of z-library and use the email to kindle tool. I haven't given Amazon a penny other than from the original purchase of the kindle. I only have used epub/pdf (and will never have a need for another format).
  - boredhedgehog 4mo ago
    Technically you already have need of another format, because Kindles don't support epub, and your books get converted before the transfer.
    - maratc 4mo ago
      The "Send to Kindle" page only accepts ePub, as to whatever format is used internally I couldn't care less.
    - WorldMaker 4mo ago
      The latest Kindle formats are just epub with a different DRM hat. Amazon still prefers to wrap the entire container in DRM whereas most epub DRM schemes are inside the container (ZIP file), but that's the only big difference now.
  - RetroTechie 4mo ago
    Quoted from here: https://informatecdigital.com/en/Send-to-Kindle%3A-all-ways-to-send-books-and-documents/ https://informatecdigital.com/en/Send-to-Kindle%3A-all-ways-... "This service is free and works with both Kindle devices such as with the Kindle appIt also automatically converts many files to Amazon's internal format (such as AZW3 or KFX), as long as you respect its supported file types and size limits." Read: requires internet connectivity to put documents on your Kindle. Depends on Amazons 'blessing'. Ends when Amazon ends support for your device. Is limited to whatever document formats (and sizes) Amazon decides to support. Internal formats on your Kindle may be DRM locked. Amazon could snoop any document transferred through that service. Could be turned into a paid service @ some point. Amazon could effectively brick your device if so desired. (please correct if I misunderstand any of the above) Sure, this may work for many users & they may be happy with that arrangement. But it's quite a few drawbacks. And the "planned obsolesence" smell is strong here. Me... I'll pass.
willXare 4mo ago
[flagged]
bayindirh 4mo ago
When using Kobo readers, using Calibre and Kobo utilities, which transparently "upgrades" your ePUBs to KePUBs without altering the copy on your disk is a must, and a huge win. Kobo's added features on top of ePUBs are nice, and their renderer is much better than Adobe's standard pipeline. So, it's a free upgrade with a terrific local library added on top.
dmang-dev 4mo ago
[flagged]
p-t 4mo ago
imho for a standard epub there should be as little CSS as possible
aboardRat4 4mo ago
Hot take: you don't need CSS in your book, a few of <style:'width: 100%;'> is enough.
rglover 4mo ago
Mentioned at the end, but Kobo's gel better with the KEPUB format. Calibre has a nice converter for this (I think it may be built-in now or still a plugin), but works great. Got a Kobo Clara Colour about ~2 years ago now and I couldn't highlight across pages until I bulk converted my library to KEPUBs. After that, you'd never know there was an issue. This post makes the whole mess make a lot more sense now.
cjfidpwmwn 4mo ago
Is it just more or hn has become a place to come and complain and consume tech drama disguised as a tech forum? It's all "I hate dario ", "I hate altman", "corporations are evil". It's getting very tiresome.
projektfu 4mo ago
This was originally posted with the full title, which made sense. Why was it truncated?
- Retr0id 4mo ago
  Presumably to make it sound less like LLM output.
  - projektfu 4mo ago
    I just don't get it when the title changes to something uninteresting. It wasn't click-bait before, but now it's almost meaningless.
mawise 4mo ago
Sharing my experience as a tinkerer, sideloader, and recent Kobo owner. I used a Kindle for ages, always in airplane mode and only sideloading content. Honestly, it was a pretty good setup.[1] But it seemed like it would be harder to setup this way on newer devices, so when mine finally failed, I got a Kobo Clara BW. I was thrilled I could boot it up in "sideloader mode" and not even register it or enable wifi. I noticed poor typography on my epubs, learned about converting to kepub so I did that (which helped). It was a familiar flow to what I was used to converting to azw3 for the Kindle. My remaining typography gripe with kepubs is that it treats a word+em-dash as a word for inserting space in full justification. Em-dashes generally don't have spaces on either side, this often looks like a space has been inserted only to the right of the em-dash. I went down the rabbit hole of NickelMenu and other readers including KOReader and Plato, and even tried (and mostly failed) to vibecode my own opds client app. (because KOReader which has one built-in felt overwhelming) My current sense is the device feels so much more like it is mine. I have much more flexibility to tinker with it. It is not as polished as the Kindle and the Adobe rendering feels stupid, but that's also a sharp edge that only the side-loading community will hit, most of whom use Calibre which can auto convert to kepub for them. Everyone else is buying books from the Kobo store and getting them delivered as kepubs. So in the end, I'm a big fan of the Kobo devices. [1]: Except you cannot remove a wifi password if you aren't in range of that wifi signal. I had a rude experience when my two-year-old was fiddling with my Kindle at my in-laws' house and turned on the wifi where there was still a saved credential. An update triggered immediately and I was frustrated for days that everything in the UI changed.
- GoblinSlayer 4mo ago
  > An update triggered immediately and I was frustrated for days that everything in the UI changed. You tried to forget that you don't own anything.
KerrickStaley 4mo ago
I use KOreader on my Kobo, which is an alternative open-source ebook renderer. It installs pretty easily without rooting the device. In addition to better standards compliance it also is a lot more performant and has niceties like auto cropping of PDFs.
murzynalbinos 4mo ago
epubcheck doing its job perfectly while Adobe's ancient RMSDK (frozen somewhere around 2013) silently chokes on valid CSS4 like min() is peak digital publishing pain. The fact that Kobo routes normal .epub to the Adobe engine and only .kepub.epub gets the modern WebKit one feels almost malicious.
watersb 4mo ago
I wonder what this writer's ePub are like. I can't tell what the writing or design are like, because the article renders as a blank page on my old iPad. Also on my 2026 Kindle Paperwhite. It's futile to be old man yelling at cloud on HN, but I'm still irritated by web pages that are essentially text, yet can't be bothered to actually display anything. A blank page. Presumably ePub publications are easier to QA than web pages. They must conform to a subset of web standards.
paradox460 4mo ago
It constantly amazes me that something like Koreader is so good, yet software made by paid professionals can be so bad. Surely it would be easier for someone like kobo to just use Koreader, implement their ui changes and demand as plugins or patches, and forget ade

919 points by sohkamyung 4mo ago

The TLDR version is Abode supports backward compatibility ... and epub - * International Digital Publishing Forum* - is playing with a sprawling mess opting for the race to the top newest standards ... that always works so well and ensures the user base is always upgrading. I'm very grateful for this information and it explains why I've avoided epub opting for pdf over epub as my reader software is old. I'm am very much on the side of supporting backwards compatibility. It reminds me of the times the M$ used to upgrade their doc standards ... where if one hadn't upgraded, well bad luck.

simcop2387 4mo ago
I think its one reason ive been happy with software based epub readers where upgrading is usually reasonable to do. Either on my phone or android based eink reader. That said if they change too much then yea nobody will produce the new standard and only support the old one if it isnt carefully designed for graceful degredation.
MrLeap 4mo ago
An epub is just a plain html webpage compressed into a zip and its extension changed from .zip to ".epub". Assuming you have a web browser, you have something that will almost certainly render your epubs contents. PDF is not nearly as pleasant under the hood. It's down right lovecraftian.
- ablob 4mo ago
  The lovecraftian horror of pdf mostly comes into play through the sheer amount of software that supply almost correct pdf. It's not enough to be able to read pdf anymore, you also have to be able to deal with software that emits subtly wrong documents.
  - PunchyHamster 4mo ago
    Adobe really have perfected act of making the most shoddy software that is still possible to sell
    - m463 4mo ago
      I'm reminded of "PSD is not my favourite file format." https://b3n.org/psd-is-not-my-favourite-file-format/ https://b3n.org/psd-is-not-my-favourite-file-format/ or in the code: https://github.com/gco/xee/blob/master/XeePhotoshopLoader.m https://github.com/gco/xee/blob/master/XeePhotoshopLoader.m
  - rcxdude 4mo ago
    That's part of it, but the design of PDF really doesn't help
- goodmythical 4mo ago
  I was floored to discover this recently when I clicked "edit" in calibre for the first time a few weeks ago. Straight HTML, edit anything everywhere. Super slick.
- anenefan 4mo ago
  I'm aware thanks. Mostly it's just my preferred viewer is older than css4 but it's been nice to find out why that was the case. PDFs can be painful as well, more often it's then using abode's pdf viewer, but it's far less common for me. There was a time many years ago when I understood PDF structures better, back when I chose to manually edit and fix a couple of malformed PDFs.
gsnedders 4mo ago
To be clear, ADE’s behaviour is not conforming to any version of the standards it claims to implement. If it had been, it would reject that specific max-width property declaration as having an invalid value and ignore it, not reject the entire document: every single version of CSS has required that forwards-compatible behaviour. PDF is not somehow immune to this either — a non-conforming implementation could similarly break what are meant to be forward-compatible extension points by raising an error on an unknown stream or object instead of (as required by the standard) ignoring it.
- anenefan 4mo ago
  So if I understand correctly a struggling epub viewer or ADE should skip css that it considers malformed - which means the reason my viewers have considered a epub to be not able to be viewed / corrupt / whatever it is for some other reason than more recent / current css implementation. PDFs certainly can suck, more often those that will only work with abode's software and other viewers I've tried can not.
  - gsnedders 4mo ago
    While plausible, I would suspect it’s more likely you’ve just run into bugs than forwards-compatible error behaviour — most ePubs don’t get anywhere near actually interesting CSS!

L-four 4mo ago

It's always CSS.

m463 4mo ago
compatible style stuff

charcircuit 4mo ago

>but it can’t validate CSS against a renderer which is fundamentally broken! The epub standard doesn't say what version of CSS must be supported. There were no guarantees modern CSS would work so I wouldn't call the renderer broken.

ninth_ant 4mo ago
If the renderer completely fails because of a minor issue when parsing the css, that is broken.
nightpool 4mo ago
No, the CSS spec is specifically designed to be forwards compatible because of exactly this issue. Any invalid CSS rule should only cause that specific line to be ignored, not the whole stylesheet. And certainly even if your CSS parser chokes in some specific case, it shouldn't cause your ereader to fail to load the entire book!
gsnedders 4mo ago
You are of course correct that ePub nowadays doesn’t mandate a given version of CSS (though earlier versions did!), but that doesn’t matter in this case: it’s non-conforming according to even CSS level 1 (1996), per https://www.w3.org/TR/REC-CSS1-961217#forward-compatible-parsing https://www.w3.org/TR/REC-CSS1-961217#forward-compatible-par... > illegal values, or values with illegal parts, are treated as if the declaration weren't there at all So a conforming implementation would ignore that max-width property declaration, not raise an error. And those earlier versions of ePub which defined a required subset of given CSS standards? The forwards-compatible parsing rules were part of their subset.
acdha 4mo ago
The parser is broken. The CSS standard says that parsers MUST ignore properties they don't recognize.
Ardren 4mo ago
ePub3 is CSS2.1 (+ some extras) CSS21 standard says "Illegal values. User agents must ignore a declaration with an illegal value." Ignore != Fatal error

tech234a 4mo ago

Adobe Digital Editions and RMSDK were recently sold to Wipro Engineering: https://helpx.adobe.com/enterprise/kb/eol-faq-adobe-digital-editions.html https://helpx.adobe.com/enterprise/kb/eol-faq-adobe-digital-...

thisislife2 4mo ago
Sold or outsourced?
- Finnucane 4mo ago
  'transitioned'
- wut42 4mo ago
  > Wipro now manages and distributes any new updates, enhancements, bug fixes, and support requests directly > Create your new ByteBooks ID using the same email address that you used for Adobe ID Seems sold mostly.

jwrallie 4mo ago

> When I started out, I dreaded the moment when I hit the validate button on my finished book after months of work, because it would always find something to cry about. I remembered one particular master student on the verge of tears trying to compile his LaTeX thesis draft, he took the “write and think about formatting later” too literally and was trying to compile it for the first time very close to the deadline.

gnatolf 4mo ago
Which, to be fair, overall probably still saved quite some time. The compile times alone would've meant they wasted so much more time by repeated earlier checks. Whether a looming deadline changed the perception about that, we don't know ;-P
samtheDamned 4mo ago
This is similar to my experience doing a research project for a fellowship. I had a barebones LaTeX file but I pushed doing the proper formatting for when I was finished writing and then had a hell of a time trying to get it all working properly right before the submission date haha.

tannhaeuser 4mo ago

Unfortunately, epub and epubcheck isn't the great uncontroversial resource the author makes it out to be. When W3C, Inc. took over maintenance of the EPub spec around when 3.1 was current, they just referenced WHATWG HTML and other ever-expanding browser specs ([1]). Being "living standards", these have no versioning or QA. As a consequence of being based on a version of HTML that redefined headers and sectioning, Epub 3.2 just made existing epubs non-conforming. Which is why Calibre and other tool still recommend 3.1 or better yet 2. The case mentioned where the CSS min() function is rejected is another place where bulk import of the extremely complex CSS spec is just not helpful. Ebook readers aren't evergreen browsers after all. [1]: https://news.ycombinator.com/item?id=41326179 https://news.ycombinator.com/item?id=41326179

ramblurr 4mo ago
Yes, it is widely known in the epub space that targeting 3.1 or 2 is the more sane option. With EPUB compatibility issues CSS should always be suspect number 1. Using "modern" CSS features and complaining about missing flex boxz grid, etc is a web developer's mindset. Just because EPUB shares some of the stack with the web doesn't mean they perfectly overlap (or even should). Hardly any e-ink embedded e-reader devices use a browser for rendering, they all use purpose built HTML/CSS parsing and rendering toolchains, are baked into firmware and updated once in a blue moon. (If you're interested look at koreader's crengine or Crosspoint reader which runs on an ESP32!) The blog post reeks of overly confident AI prose. But don't be fooled.
- lavela 4mo ago
  Shouldn't a CSS engine just ignore directives it doesn't know? At least it shouldn't fail without an error.
  - jiehong 4mo ago
    Came here to say exactly that: CSS was designed to be friendly and just ignore any line it doesn’t understand. It’s the whole point of browsers and progressive improvements.

lidavidm 4mo ago

AIUI, Kobo devices have a more advanced rendering engine if you name the file with .kepub.epub. (I think it's based on ePub 3?) Not sure if it would fix the problem here. But I personally run ePubs through kepubify (https://pgaskin.net/kepubify/try/ https://pgaskin.net/kepubify/try/) before transferring them to my Kobo.

louisbourgault 4mo ago
Yes, I do that for everything too. Also publishers like Standard ebooks provide a kepub download - as they explain here they have problems with the Adobe reader too. https://standardebooks.org/help/how-to-use-our-ebooks#kobo-faq https://standardebooks.org/help/how-to-use-our-ebooks#kobo-f... I love my Kobo (clara colour) and really, if they just removed the Adobe reader, it'd be perfect. And yes, I've tried KOreader, but never switched to it because I like my Overdrive library books and Kobo Store.
- buu709 4mo ago
  > I love my Kobo (clara colour) and really, if they just removed the Adobe reader, it'd be perfect. And yes, I've tried KOreader, but never switched to it because I like my Overdrive library books and Kobo Store. You may have already tried this, but they all work fine together. You can just exit the KOReader app and use the default Kobo stuff, then open KOReader again when you want to read something via that.
FinnKuhn 4mo ago
Looks like this info was added to the post as an update.

acdha 4mo ago

Adobe has always been like this, too. They squandered an enormous marketshare with Flash because the alternative would've been spending a couple million on QA and they managed to unite all of the browser manufacturers in agreement that the web was better off without such an unreliable partner. I shipped a couple of things on Flash back in the day but it was staggeringly bad software — random crashes, various heisenbugs where changes in one area would affect unrelated functionality in other modules, etc. — and while it cost something like $800, it was completely unsupported: I filed a number of trivially reproducible bugs with reduced test cases but never heard anything back until the next release came out and they sent automated suggestions that the bug might be fixed so I should buy a full-price license and find out.

echelon 4mo ago
Flash is still unsurpassed as the easiest publishing medium. JavaScript build system layer cake and "web standards" are a million times harder than just drawing some stuff, maybe writing a simple function, then building a static file that can be embedded anywhere and even downloaded. You have to spend so much time setting up any flash alternative, and the "standards" are worse. I hate Steve Jobs for killing Flash and Adobe for being such awful stewards of one of the most amazing web technologies. Kids growing up today have no idea how magical Flash was. It was like Roblox or Minecraft for web. Websites are still inferior to Flash of the early 2000s. It's taken decades and they can only mimic a fraction of its power. And none of its ease.
- LeFantome 4mo ago
  You know you can use Ruffle if you really want Flash right? https://ruffle.rs https://ruffle.rs But the only standard you need is WASM. All browsers support it. Use whatever you want to make it. In fact, Ruffle is just a WASM app.
  - ameliaquining 4mo ago
    The problem is that, while there's no theoretical barrier to an authoring tool with a Director-like user experience that exports to Wasm, no one has actually written one, and it's not a small amount of work. (I agree that we're better off without Flash, but this particular problem is real and unsolved.)

TeaVMFan 4mo ago

When building EPublish ( https://frequal.com/epublish/ https://frequal.com/epublish/ ), an HTML-to-epub converter, I faced similar hurdles. Trying to keep compatibility with numerous e-readers built with different stacks and varying degrees of EPUB versions is frustrating. I used EPublish for my first novel, Means and Motive, just published here, DRM-free: https://www.amazon.com/dp/B0GYCZJVGX https://www.amazon.com/dp/B0GYCZJVGX So far I haven't heard of compatibility issues, so I think EPublish has hit the sweet spot of EPUB targeting. I agree, however, that it feels like the old days of targeting IE6 on the web. Old readers still exist out there, so we have to aim for the lowest common denominator.

badsectoracula 4mo ago

Be happy your readers use an ePub reader that supports (or at least, ignores) something like `max-width` in the first place :-P. TBH i've being using an ePub reader that i occasionally had to edit ePub files so i get rid of the superfluous styling that made it either not work or show things weirdly/wrong and i've heard comments from others that a bunch of files i had no issues with personally were unreadable for them, which makes me think that unless you really and absolutely need any fancy formatting (i.e. math stuff that can't just be made images - and you really tried to!) then you should stick with the most basic HTML imaginable - things that not even IE4 would render (too) wrong. And in turn, since i doubt this will ever happen, i sometimes ponder making an "epub reconstruct" tool that attempts to reconstruct epubs so that they use the simplest HTML/CSS :-P (ideally configurable for maximum compatibility).

thatguy00 4mo ago
Ah, yes. When I paint, I also leave the middle unpainted, in case some people have a crack in their glasses that would make the painting look weird. Or maybe we should tell glasses makers to make better glasses and let the artists make their art.
- teddyh 4mo ago
  People making shows for TV had to respect the TV ”safe area”: <https://en.wikipedia.org/w/index.php?title=Safe_area_(television)&oldid=1289553744 https://en.wikipedia.org/w/index.php?title=Safe_area_(televi...>
dlcarrier 4mo ago
It's already bad enough that HTML/CSS barely works in the target web browser environment, I don't see why anyone decided it was a good idea to use it for books. I've often thought about figuring out a subset that operates fast on any computer and sticking to that for any web pages I make. If someone figured that out for epub, it would make it much, much more useful.

WolfeReader 4mo ago

Every Kobo reader is capable of running KoReader ( http://koreader.rocks/ http://koreader.rocks/ ). That's the first, and probably last, step I'd take to render a book that the default reader takes issue with.

criddell 4mo ago
As I understand it, KoReader doesn’t work with drm protected books which means I can’t use it with most books I buy. Ebook producers really should be forced to either drop drm or adopt a cross-platform standard.
- downsplat 4mo ago
  Search around, there's surely a way to break the drm. When theres no better way that's what I do too: pay for the book, convert to plain epub. The publishing industry never got its head out of... some dark place. We've been able to buy mp3s without drm for ages, but somehow books are different.
  - sync 4mo ago
    If you have a ACSM (the file type Adobe Digital Editions uses for DRM) I’ve been using https://www.acsm-converter.com https://www.acsm-converter.com to strip the DRM and return a standard epub
- troyvit 4mo ago
  It's probably too annoying for most, but I had a similar problem with KoReader and library books because those too depend on DRM. I ended up keeping KoReader as an app, then just not loading the app when I was reading a library book. It wasn't too bad. KoReader also gave me a lot of freedom to manage the bad battery life of my Kobo Sage before it died of other causes. Definitely worth the extra cognitive load of dealing with the two experiences.

Javalicious 4mo ago

Wow. This brings up some (bad) memories of working with an .epub export about 10 years ago. We had some embedded fonts to work around some poor rendering in some of the readers we tested, but some of the readers ignored the fonts altogether, causing the content to render boxes (bangs head on table) It looks like not a whole lot has changed in that space -- the readers are still the gate for what you can do with the format. Who's available to make a CanIUse for epub readers, to shame them into compliance? (only partly /s)

nfw2 4mo ago

As someone who has spent a good deal of time trying to build ereader software, eventually I decided to try to deal with the devil and build on top of RMSDK. There is no way to get access to it. I don't mean the licensing cost is prohibitively expensive for an indie dev although I understand that to be the case as well. There is no one to talk to. The email listed on their website does not respond to anything. Not even so much as a "Thanks for your interest" or a "We will get back to you". I messaged a former colleague who worked there to try to see what the process is to get access to rmsdk. He said he tried to find internal docs about it and couldn't find anything. I tried to find people on linkedin who might be associated with rmsdk and ask them and similarly found nothing. Meanwhile publishers only distribute most of their titles with one of their known drm vendors ie Apple, Amazon, or Adobe. The other two are entirely closed off. If this isn't anticompetitive trust behavior, I don't know what is.

stonecharioteer 4mo ago
Hello, I'm building https://merrilin.ai https://merrilin.ai, could I pick your brain about the problems you faced?
- nfw2 4mo ago
  Sure thing. I've actually been working on the spoiler-free resource angle as well. I can book a call to talk. Distribution is the killer problem here though.
  - sanex 4mo ago
    I thought about building this too! Love that both of you are pursuing it as I haven't had the time to start. Don't give up.
    - stonecharioteer 4mo ago
      Yay! Registrations to https://merrilin.ai https://merrilin.ai are open and you can enjoy a free account for as long as I can afford to give it (I have no funding lol). The android app is ready for closed testing too, if you have an Android device, mail me at mail [at] stonecharioteer.com and I'll add you to the beta testing. ios is still a pain.

naikrovek 4mo ago

Death to Adobe. For this reason and 10,000 others.

danpalmer 4mo ago

> Epubcheck does basic CSS checking of course, but it can’t validate CSS against a renderer which is fundamentally broken! But isn't that kind of the point of epubcheck? It's surely not intended to validate all of CSS, it's intended to validate that an epub will work... and not working on Kobo devices (probably #2 manufacturer of ebook readers?) is a major issue.

gsnedders 4mo ago
epubcheck is meant to ensure conformance with the standards, not the interoperably implemented subset of the standards. (Which has lots of awkward questions: which implementations of the standards, which versions of those implementations, etc.)
- ameliaquining 4mo ago
  The latter seems like what the tool's users actually want. That it's a harder problem doesn't change that.
  - MadnessASAP 4mo ago
    The user wants the website to work in IE6, developing and testing only against IE6 to the detriment of other browsers is not generally regarded as a healthy state of affairs. The standard exists, it is the responsibility of both the producer and consumer of ePUB files to adhere to the standard. https://en.wikipedia.org/wiki/Robustness_principle https://en.wikipedia.org/wiki/Robustness_principle
    - ameliaquining 4mo ago
      If a large fraction of your users are on IE6 and you can't realistically get them off it, you need to make sure your site works in IE6, and good tooling should help you do this. Of course you also want to make sure it works in other browsers your users use, and a standard may be helpful in doing that.
  - 4mo ago

chocolatkey 4mo ago

Kobo is actually in the process of completely rewriting their e-reader software (you can download the beta in the EU), and I’m pretty sure it’s no longer based on RMSDK. Adobe basically handed the EPUB DRM market to LCP on a silver platter by being a poor maintainer and then selling off to a third party that had botched the migration and further angered end users and platforms, that are switching off Adobe faster than ever

el_benhameen 4mo ago
Have you tried the beta? Have you found it to be substantially better?
- chocolatkey 4mo ago
  I’m not in the EU so I have not, this is based on the technical changes mentioned, and what I’ve heard from people. Feel free to try if you are in the EU: kobo.com/update
anilakar 4mo ago
Only in EU because of the Accessibility Act[1]. Copywrong holders are allowed to disable screen readers elsewhere because that allows them to sell more audiobooks. You will apparently also lose many other features, among them Asian scripts and developer mode. [1] https://www.kobo.com/kobo-writing-life/blog/our-commitment-to-accessibility-and-the-european-accessibility-act-eaa https://www.kobo.com/kobo-writing-life/blog/our-commitment-t...
BoingBoomTschak 4mo ago
Interesting news! Though I'm on https://koreader.rocks/ https://koreader.rocks/ like most people here, I suppose.

dottchen 4mo ago

BOOX works fine. One solution is to ask Codex to reformat your epub file before importing it to your ereader.

tcoff91 4mo ago
I love my Boox, I run Storyteller on it instead of the native e-reader. I love that it’s just an android tablet with an e-ink screen.
yoavm 4mo ago
BOOX devices are great except for the GPL violation. It's really a shame.

boznz 4mo ago

For my free novels which I deliberately keep the styles to header2 and body text, it is surprising the amount of crud that all the ePub conversion softwares generate, especially since they are just zipped web-pages. These days I usually get 90% of the way on google docs, then do the final editing on LibreOffice which can add things like tables of contents and cover image, if it opens on Kindle, Kobo and Calibre I consider it job done.

GreenSalem 4mo ago

"EPUB is an amazing open standard for ebooks, and yet so many implementations of it are just fundamentally flawed, all in the name of keeping IP lawyers happy." Easy to be dismissive, but IP violations can cost a large company hundreds of millions. IP lawyers are more important to many companies than their software developers. If you doubt that, check to see who gets paid more...

unnouinceput 4mo ago

I don't like .epub. I understand the reasons why this format exists, and I am 100% behind those reasons. But it's because I don't find any EPUB readers appealing to me. Just give me a FoxIt Reader clone for .epub, that's all. But naaaah!!, every single fucking e-pub reader that I tried must be a fucking library collector instead, like it's 2000's Windows Media Player style. I hate that. As such, whenever I get my hands on an .epub file, I go to an online converter, convert it to a .pdf file and nuke it from my system. Then the .pdf gets opened in my FoxIt.

__float 4mo ago
Hmm, Sumatra PDF perhaps?
pteraspidomorph 4mo ago
Have you tried foliate? Their embedded reader works quite well for me.
stonecharioteer 4mo ago
As someone who loves FoxIt reader, I'm building https://merrilin.ai https://merrilin.ai to be the best damned ebook reader out there, to support PDF and epub. FoxIt's annotation system is one of the best I've experienced and I want to design one that is just as good if not better.
- gabrieletrovato 4mo ago
  Building a robust annotation system for both PDF and EPUB is a tough technical challenge, but definitely needed. I've been working in a similar space and recently open-sourced it. It's a local-first 3D library for organizing and reading EPUBs and PDFs directly in the browser. It's called KoreShelf on Github
  - majora2007 4mo ago
    I just released a pretty solid annotation system for Kavita's EPUB reader. It wasn't super challenging (although Kavita has a custom epub renderer). Now doing that with PDF would actually make it challenging. Annotation system (with pics): https://wiki.kavitareader.com/guides/readers/epub/#annotationshighlights https://wiki.kavitareader.com/guides/readers/epub/#annotatio...

hardwaresofton 4mo ago

BTW for those who are looking for a device, the PineNote exists: https://pine64.org/devices/pinenote/ https://pine64.org/devices/pinenote/ More expensive and less out-of-the-box software, but straight to the point on device ownership/what kind of software you can run, fewer strings attached. [EDIT] Great experience blogs on the PineNote https://shom.dev/posts/20250308_pinenote-day-one/ https://shom.dev/posts/20250308_pinenote-day-one/ https://shom.dev/posts/20250406_a-pinenote-only-5-day-weekend/ https://shom.dev/posts/20250406_a-pinenote-only-5-day-weeken...

ndiddy 4mo ago
Have you tried the PineNote yourself? It $400 and says that it's "aimed at Linux developers with an extensive knowledge of embedded systems and/or experience with mobile Linux." The community provided firmware they link for it hasn't been updated in over a year. The Kobos don't limit what you can do with them either, you can sideload alternative e-reader software like KOReader that improves on the built-in reader functionality.
- hardwaresofton 4mo ago
  > More expensive and less out-of-the-box software, but straight to the point on device ownership/what kind of software you can run, fewer strings attached. This note was in the original comment, did you read it? The fact that it is $400 (more expensive) and has less out of the box software is literally mentioned to alert people to that. > The Kobos don't limit what you can do with them either, you can sideload alternative e-reader software like KOReader that improves on the built-in reader functionality. This is patently false, the latest Kobo Libra Color is using secure boot which completely locks out custom development: https://www.mobileread.com/forums/showthread.php?t=363175 https://www.mobileread.com/forums/showthread.php?t=363175 So much so that QuillOS which used to be Kobo focused rewrote to support the PineNote https://github.com/Quill-OS/quill https://github.com/Quill-OS/quill https://quill-os.org/ https://quill-os.org/ The point is to buy hardware that is built for you to freely modify and fully own, from the start. My post was to make sure everyone knew the PineNote was an option, because I certainly did not know it until someone on HN made me aware. Could you maybe make your point more concrete? Are you attempting to completely dissuade people from using the PineNote because it may not be easy to side load apps to it on hacker news?. Obviously different people have different propensities to do hacking, and some may not be able to afford the PineNote due to how expensive it is, but it's not clear what the goal of your comment was. If your goal was "invest in Kobo instead of PineNote", I disagree with that. I'm not interested in investing (whether money or time) in an ecosystem that is just going to rug pull me eventually, over nickels and dimes. BTW for those who agree, another great option is XTeink -- very hackable, and I've bought one myself: https://www.xteink.com/ https://www.xteink.com/ And there's a Linux phone out there which looks pretty encouraging too: https://furilabs.com/shop/flx1splus/ https://furilabs.com/shop/flx1splus/ Graphene is likely still the easier more polished option, but it's great to have options these days.

gcanyon 4mo ago

Is there a way to root the kobo and put a modern renderer in place?

MadnessASAP 4mo ago
Yes, for the ones I've owned rooting is very easy. KOReader and Plato are both popular (amongst the community of eReader rooting people) alternatives to the OEM software.
t-3 4mo ago
It runs a standard linux and mounts as external storage when connected over USB. No need to "root" at all.
WorldMaker 4mo ago
The article's update points out that it switches to a modern renderer if you rename .epub to .kepub.epub, which seems like a dumb way to handle that rather than a DRM existence/version check, but that's not entirely unusual for backwards compatibility support shenanigans. (Others point out that Calibre automatically will rename epub files to .kepub.epub for you if you use it to manage a Kobo library. It's just manually copying files to Kobo where you need to remember to do it yourself if you have a Kobo.)

itsthecourier 4mo ago

bro, what an anchor to the past that framework is

BonoboIO 4mo ago

[flagged]

Edwingg 4mo ago

[flagged]

Edwingg 4mo ago

[flagged]

k_sze 4mo ago

The author says that "In a perfect world, RMSDK would just stop living in the CSS stone-ages or at least provide some kind of error handling instead of dropping the whole book, but I’m not holding my breath." This is blatantly wrong. In a perfect world, RMSDK wouldn't exist in the first place and Adobe would have gone bankrupt and become history at least 10 years ago.

m463 4mo ago
Actually - in a perfect world steve jobs would have written a missive about it and killed it from orbit. https://en.wikipedia.org/wiki/Thoughts_on_Flash https://en.wikipedia.org/wiki/Thoughts_on_Flash https://web.archive.org/web/20170615060422/https://www.apple.com/hotnews/thoughts-on-flash/ https://web.archive.org/web/20170615060422/https://www.apple...

mannyv 4mo ago

"Epubcheck does basic CSS checking of course, but it can’t validate CSS against a renderer which is fundamentally broken!" According to the author, Kobo uses CSS from 2013. A quick check with an AI says RMSDK supports CSS 2.1 and parts of 3. So it's not that the renderer is broken, it's that he believed that epubcheck actually checks against devices and the versions of CSS that those devices support. This is exactly the issue with test tools: the test tool tests to a spec, but the platform is the gold standard. If you don't like it tough shit.

WorldMaker 4mo ago
The CSS 1 spec says to robustly ignore lines you don't understand. Adobe didn't need to predict CSS 4, they needed to better implement CSS 1.

pmontra 4mo ago

I understand the frustration of the author but how many readers do have an old, unupgraded, maybe unupgradable epub reader? If authors want to make their work available to all readers they have to build for the least common denominator. If it happens to be something from 2013, sorry but that's the reality of the market.

graeme 4mo ago
I read this as saying a new Kobo in 2026 uses Adobe drm software that has css rules stuck in 2013.
qubidt 4mo ago
The issue the author is explaining is relevant for the Kobo devices currently being sold

protocolture 4mo ago

I once read an ebook that was formatted by a guy who had only ever done magazines and it was a huge mess. 2 columns of text per page. No auto scaling. The best ebook format I have ever experienced is .txt and just let the software figure out where the text needs to go.

microflash 4mo ago
Many ePub readers allow you to ignore formatting. And that’s exactly what I do.
TiredOfLife 4mo ago
The best format was fb2
- Self-Perfection 4mo ago
  Why "was"? I still read books in fb2.

nanapipirara 4mo ago

I’m supposed to be able to lend ebooks from my local library. Adobe makes it impossible as their software doesn’t run on my macbook…

themadturk 4mo ago
Adobe Digital Editions runs on my MacBook Air M3 with macOS Tahoe. What problem do you see? (FWIW, ADE will probably die when Rosetta support goes away with MacOS 28, but one of the de-DRM plugins will read acsm files directly and bring in the books.)

insumanth 4mo ago

> that bloated pinnacle of software that is 80% about DRM, 20% about the reading experience I have never seen someone explain the adobe software so perfectly. Using any adobe software is exactly this.

matwood 4mo ago
Unfortunately this is any reader software that deals with publishers who require DRM. IME, the vast majority of bugs also come from the DRM.

latexr 4mo ago

I’m curious if simply running the original EPUB through Kepubify fixes the problem. https://pgaskin.net/kepubify/ https://pgaskin.net/kepubify/

bowsamic 4mo ago

ePub compatibility issues are one of the worst parts of having a Kobo reader. I genuinely miss my Kindle and its simple but reliable MOBI format. At least there everything worked

ornornor 4mo ago
I don’t miss my kindle, at all. Its text layout engine was a joke (every page edge was ragged!), you depend very heavily on amazons goodwill to keep allowing you, the device owner, to sideload your own books, it’s getting harder to install third party software, and well that one is personal but it’s from Amazon. I’ve switched to kobos (Clara HD) and I’ve had to for years. It’s chugging along (had to 3d print a replacement power button a couple months ago), I can run koreader no problem and use calibre with the kobo plugin. And the default rendering engine in kobo’s firmware does actually typeset the text: no ragged edges!

ceving 4mo ago

If nobody is able to implement the standard it is probably not amazing.

ornornor 4mo ago

If you use a kobo you have to give koreader a whirl! The only thing missing for me is the unified view of the library: koreader requires you to navigate to the subdirectory to open your ebook whereas nickel (kobo’s UI) will list them all in one library regardless of how deeply nested they are. Everything else is better with koreader and it’s super easy to install alongside nickel. And it works very well with calibre + the kobo plugin.

martin- 4mo ago
There are several plugins that give you a library view based on metadata instead of folders and filenames. Two examples that are both great: https://github.com/AndyHazz/bookshelf.koplugin https://github.com/AndyHazz/bookshelf.koplugin https://github.com/joshuacant/ProjectTitle https://github.com/joshuacant/ProjectTitle
- ornornor 4mo ago
  Thanks, I had no idea, these look great!
themadturk 4mo ago
You can also play with Calibre's default transfer template so all book files go into a single folder of your choice on the device. Then you can set your KOReader home or favorites folder and see everything in one place.

icantevenhold 4mo ago

I recently was in the market for a new e-reader and steered away from Kobo and Kindle because of their non-free ecosystem. I don’t know how exactly it would negatively impact me but I didn’t want to find out. Got a refurbished pocketbook in the end and very happy with it, it reads all imaginable file formats and I can just send books to it via email or cable.

dakolli 4mo ago
I don't really have an issue with kindle, I just download anything off of z-library and use the email to kindle tool. I haven't given Amazon a penny other than from the original purchase of the kindle. I only have used epub/pdf (and will never have a need for another format).
- boredhedgehog 4mo ago
  Technically you already have need of another format, because Kindles don't support epub, and your books get converted before the transfer.
  - maratc 4mo ago
    The "Send to Kindle" page only accepts ePub, as to whatever format is used internally I couldn't care less.
  - WorldMaker 4mo ago
    The latest Kindle formats are just epub with a different DRM hat. Amazon still prefers to wrap the entire container in DRM whereas most epub DRM schemes are inside the container (ZIP file), but that's the only big difference now.
- RetroTechie 4mo ago
  Quoted from here: https://informatecdigital.com/en/Send-to-Kindle%3A-all-ways-to-send-books-and-documents/ https://informatecdigital.com/en/Send-to-Kindle%3A-all-ways-... "This service is free and works with both Kindle devices such as with the Kindle appIt also automatically converts many files to Amazon's internal format (such as AZW3 or KFX), as long as you respect its supported file types and size limits." Read: requires internet connectivity to put documents on your Kindle. Depends on Amazons 'blessing'. Ends when Amazon ends support for your device. Is limited to whatever document formats (and sizes) Amazon decides to support. Internal formats on your Kindle may be DRM locked. Amazon could snoop any document transferred through that service. Could be turned into a paid service @ some point. Amazon could effectively brick your device if so desired. (please correct if I misunderstand any of the above) Sure, this may work for many users & they may be happy with that arrangement. But it's quite a few drawbacks. And the "planned obsolesence" smell is strong here. Me... I'll pass.

willXare 4mo ago

[flagged]

bayindirh 4mo ago

When using Kobo readers, using Calibre and Kobo utilities, which transparently "upgrades" your ePUBs to KePUBs without altering the copy on your disk is a must, and a huge win. Kobo's added features on top of ePUBs are nice, and their renderer is much better than Adobe's standard pipeline. So, it's a free upgrade with a terrific local library added on top.

dmang-dev 4mo ago

[flagged]

p-t 4mo ago

imho for a standard epub there should be as little CSS as possible

aboardRat4 4mo ago

Hot take: you don't need CSS in your book, a few of <style:'width: 100%;'> is enough.

rglover 4mo ago

Mentioned at the end, but Kobo's gel better with the KEPUB format. Calibre has a nice converter for this (I think it may be built-in now or still a plugin), but works great. Got a Kobo Clara Colour about ~2 years ago now and I couldn't highlight across pages until I bulk converted my library to KEPUBs. After that, you'd never know there was an issue. This post makes the whole mess make a lot more sense now.

cjfidpwmwn 4mo ago

Is it just more or hn has become a place to come and complain and consume tech drama disguised as a tech forum? It's all "I hate dario ", "I hate altman", "corporations are evil". It's getting very tiresome.

projektfu 4mo ago

This was originally posted with the full title, which made sense. Why was it truncated?

Retr0id 4mo ago
Presumably to make it sound less like LLM output.
- projektfu 4mo ago
  I just don't get it when the title changes to something uninteresting. It wasn't click-bait before, but now it's almost meaningless.

mawise 4mo ago

Sharing my experience as a tinkerer, sideloader, and recent Kobo owner. I used a Kindle for ages, always in airplane mode and only sideloading content. Honestly, it was a pretty good setup.[1] But it seemed like it would be harder to setup this way on newer devices, so when mine finally failed, I got a Kobo Clara BW. I was thrilled I could boot it up in "sideloader mode" and not even register it or enable wifi. I noticed poor typography on my epubs, learned about converting to kepub so I did that (which helped). It was a familiar flow to what I was used to converting to azw3 for the Kindle. My remaining typography gripe with kepubs is that it treats a word+em-dash as a word for inserting space in full justification. Em-dashes generally don't have spaces on either side, this often looks like a space has been inserted only to the right of the em-dash. I went down the rabbit hole of NickelMenu and other readers including KOReader and Plato, and even tried (and mostly failed) to vibecode my own opds client app. (because KOReader which has one built-in felt overwhelming) My current sense is the device feels so much more like it is mine. I have much more flexibility to tinker with it. It is not as polished as the Kindle and the Adobe rendering feels stupid, but that's also a sharp edge that only the side-loading community will hit, most of whom use Calibre which can auto convert to kepub for them. Everyone else is buying books from the Kobo store and getting them delivered as kepubs. So in the end, I'm a big fan of the Kobo devices. [1]: Except you cannot remove a wifi password if you aren't in range of that wifi signal. I had a rude experience when my two-year-old was fiddling with my Kindle at my in-laws' house and turned on the wifi where there was still a saved credential. An update triggered immediately and I was frustrated for days that everything in the UI changed.

GoblinSlayer 4mo ago
> An update triggered immediately and I was frustrated for days that everything in the UI changed. You tried to forget that you don't own anything.

KerrickStaley 4mo ago

I use KOreader on my Kobo, which is an alternative open-source ebook renderer. It installs pretty easily without rooting the device. In addition to better standards compliance it also is a lot more performant and has niceties like auto cropping of PDFs.

murzynalbinos 4mo ago

epubcheck doing its job perfectly while Adobe's ancient RMSDK (frozen somewhere around 2013) silently chokes on valid CSS4 like min() is peak digital publishing pain. The fact that Kobo routes normal .epub to the Adobe engine and only .kepub.epub gets the modern WebKit one feels almost malicious.

watersb 4mo ago

I wonder what this writer's ePub are like. I can't tell what the writing or design are like, because the article renders as a blank page on my old iPad. Also on my 2026 Kindle Paperwhite. It's futile to be old man yelling at cloud on HN, but I'm still irritated by web pages that are essentially text, yet can't be bothered to actually display anything. A blank page. Presumably ePub publications are easier to QA than web pages. They must conform to a subset of web standards.

paradox460 4mo ago

It constantly amazes me that something like Koreader is so good, yet software made by paid professionals can be so bad. Surely it would be easier for someone like kobo to just use Koreader, implement their ui changes and demand as plugins or patches, and forget ade