Why can't I upload an epub3 book to my Kobo Forma?

[droopy]

I downloaded an epub3 from https://standardebooks.org/ebooks/p-...th-in-the-city.

Kobo's help page (https://help.kobo.com/hc/en-us/artic...ks-app-support) says that Kobo ereaders support epub3.

When I try to upload the epub3 from my Calibre library, I get this error message.

calibre, version 4.12.0
WARNING: No suitable formats: Could not upload the following books to the device, as no suitable formats were found. Convert the book(s) to a format supported by your device first.

Psmith in the City epub3

Why is conversion necessary?

[theducks]

Connect your device: right click the Device Icon: Configure: TICK EPUB3

The driver serve more than 1 model. some of those do NOT support EPUB3 (the owner may have given a device firmware update notice an 'ignore' )

[droopy]

ducks,
epub3 isn't in the list of formats.

Pls see screenshot.

[theducks]

Originally Posted by droopy

ducks,
epub3 isn't in the list of formats.

Pls see screenshot.

I assume your Calibre is 4.x (the driver will be current)

Then there are 2.5 possibilities
1) The Kobo does not do EPUB3
1.5) The file must be named just EPUB <<< I think this is true

2)No one reported this bug (missing EPUB3)

[hobnail]

When you download an epub3 from Standard Ebooks the file extension on it is .epub3 so you need to delete that 3 so that it's .epub. You may need to tweak your Windows settings so that it shows you the file extensions (always a good idea in my opinion).

I don't know what the epub standard says but it wouldn't surprise me if the extension is supposed to be epub and not epub3.

Internally it's still an epub3 and the kobo will recognize it as such. I doubt if there's any advantage of downloading the epub3 over the epub2; I used to download the epub3 versions but now just get their epub2s. Somewhere I'd downloaded a book that had @ lines at the top of the css which caused my kobo to ignore all of the css; dunno if it was Standard Ebooks or somewhere else.

[droopy]

Originally Posted by theducks

I assume your Calibre is 4.x (the driver will be current)

Yes, I'm on the latest version of Calibre: 4.12.

Originally Posted by theducks

Then there are 2.5 possibilities
1) The Kobo does not do EPUB3

Hmmm... maybe you're right. I mean, the Kobo help page does say that Kobo ereader devices do support epub3. But someone else on this forum has just chimed in to say that "it's a lie". Lol.

Originally Posted by theducks

1.5) The file must be named just EPUB <<< I think this is true

Hmmm... I'd think that standardebooks.org named it as ".epub3" because that's the standard file extension for epub3 files. For me to have to change it to epub (without the number 3) seems like a workaround.

Originally Posted by theducks

2)No one reported this bug (missing EPUB3)

I'd love to get confirmation on this.

[theducks]

Originally Posted by hobnail

When you download an epub3 from Standard Ebooks the file extension on it is .epub3 so you need to delete that 3 so that it's .epub. You may need to tweak your Windows settings so that it shows you the file extensions (always a good idea in my opinion).

I don't know what the epub standard says but it wouldn't surprise me if the extension is supposed to be epub and not epub3.

It is the Internals of the book that says it is version3
This does pose a problem if the user has devices that do not support EPUB3, because you can only have 1 EPUB (filetype) file per book entry

[droopy]

How can I prevent my Calibe from auto-converting epub3 files into kepub, while still autoconverting epub2 into kepub?

[theducks]

Originally Posted by droopy

How can I prevent my Calibe from auto-converting epub3 files into kepub, while still autoconverting epub2 into kepub?

You can't (if you use Auto convert ?)
You would need to make KEPUBS first, then those get sent
You would first need to determine which books have EPUB2, then convert only those to KEPUB

[davidfor]

Originally Posted by droopy

How can I prevent my Calibe from auto-converting epub3 files into kepub, while still autoconverting epub2 into kepub?

You can't. And you probably don't want to. If you really want to use as many epub3 features as Kobo supports, you want the book as an kepub. If you use the extended driver to transform the book to kepub, it doesn't matter whether the input is epub2 or epub3. The output will not change that. And the kepub renderer will respect the epub version.

If you want to use some books as epubs (of either version) or some as kepubs, then don't use the extended driver. For the books you want to read as kepubs, do a conversion in calibre. The default configuration for the built-in KoboTouch driver is to send kepubs if they are available before epubs.

But, overall, most people choose one format or the other and stick to it. And it comes down to either wanting the extra function a kepub supplies, or wanting to avoid the formatting differences.

[DNSB]

Originally Posted by hobnail

Internally it's still an epub3 and the kobo will recognize it as such. I doubt if there's any advantage of downloading the epub3 over the epub2; I used to download the epub3 versions but now just get their epub2s. Somewhere I'd downloaded a book that had @ lines at the top of the css which caused my kobo to ignore all of the css; dunno if it was Standard Ebooks or somewhere else.

Unfortunately, the only way to have the epub recognized by the Kobo as an epub3 is to rename it to .kepub.epub which will trigger the use of the epub3 renderer. Kobo does not inspect the ebook to see which renderer to use. The rename does allow more epub3 features but highlighting and other features which depend on the spans added to a 'proper' kepub will not be happy campers. My work flow for epub3 is to run them through either the KoboTouchExtended driver or to use kepubify to add those spans.

If you use the epub2 renderer, RMSDK does have the nasty habit of dumping the CSS after it sees an error. At times, I wonder about Adobe's inability to write a decent error handler.