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- Hacker News
- 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.by pmontra
- The issue the author is explaining is relevant for the Kobo devices currently being soldby qubidt
- I read this as saying a new Kobo in 2026 uses Adobe drm software that has css rules stuck in 2013.by graeme
- When building 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
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.
by TeaVMFan - 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.
by mawise - > 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.
by GoblinSlayer - > 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.
by jwrallie - 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.by samtheDamned
- 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
by gnatolf - Adobe Digital Editions and RMSDK were recently sold to Wipro Engineering: https://helpx.adobe.com/enterprise/kb/eol-faq-adobe-digital-...by tech234a
- Sold or outsourced?by thisislife2
- 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).
- 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.by thatguy00
- 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.
by dlcarrier - 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 everby chocolatkey
- Have you tried the beta? Have you found it to be substantially better?by el_benhameen
- Interesting news! Though I'm on https://koreader.rocks/ like most people here, I suppose.
- 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-t...
by anilakar - BTW for those who are looking for a device, the PineNote exists:
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/20250406_a-pinenote-only-5-day-weeken...
- Thanks for this call out. I have not checked on Pine devices much since a disappointing early Pinebook.by pluralmonad
- I mean, it’s expensive, huge, and potentially unstable; not exactly what I’d want to read in bed at night.
The Pine projects are necessary and well-motivated, but the PineNote doesn’t strike me as a reader’s device, maybe a hacker’s or someone that wants an e-ink tablet.
by port11 - Also worth checking out, this guy's Open-Source 60hz e-ink screen: [video] https://www.youtube.com/watch?v=nHbA2-_qzH4
- One can also just run Linux on most Kobos. I wrote and am using this every day: https://github.com/bjesus/airby yoavm
- 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.
by ndiddy - 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/) before transferring them to my Kobo.by lidavidm
- Looks like this info was added to the post as an update.by FinnKuhn
- 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-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.
- 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.
by tannhaeuser - 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.
by ramblurr - 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.
by nfw2