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.

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.

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.

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.

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.

> 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.

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.

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

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.

"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.