Can I convert Epub 3.0 to 2.0?

[SigilBear]

Can I convert an Epub 3.0 that I created with Sigil to Epub 2.0?

I've found the setting in Preferences that lets me create new projects in the 2.0 format. But I'd like to make a copy of a 3.0 project and change it to 2.0.

I found this code in the content.opf file...

<package version="3.0" unique-identifier="BookId" xmlns="http://www.idpf.org/2007/opf">

But I imagine a conversion involves a lot more than imply changing version="3.0" to version="2.0."

Another possibility is that I could create a new project in 2.0, then open my 3.0 project with eCanCrusher and import the files into my new project.

[Doitsu]

There's no built-in option and no plugin for converting epub3 books to epub2 books, however, since Sigil generates epub2 compatible epub3 books by default and Amazon KDP will accept valid epub3 books as input files, there's hardly any reason to convert epub3 books to epub2 books unless your book aggregator/distributor won't accept epub3 books.

[SigilBear]

Everyone's been telling me that I should forget about Epub 3.0 and publish in the 2.0 format.

[JSWolf]

Originally Posted by SigilBear

Everyone's been telling me that I should forget about Epub 3.0 and publish in the 2.0 format.

That's because they are correct.

[DiapDealer]

Actually, no they're not "correct". A fairly decent chunk of the commercial epubs i buy and read these days are epub3.

To the OP: there is no automated way from epub3 back to epub2. Not with Sigil anyway. You wouldn't be able to change that package version attribute within Sigil even if you wanted to.

[SigilBear]

Originally Posted by DiapDealer

Actually, no they're not "correct". A fairly decent chunk of the commercial epubs i buy and read these days are epub3.

To the OP: there is no automated way from epub3 back to epub2. Not with Sigil anyway. You wouldn't be able to change that package version attribute within Sigil even if you wanted to.

OK, thanks.

I created a new project (2.0) and imported all my files from the 3.0 version. It seems to be working OK, so far. I have to reorder all my pages, but it looks like you do that by simply dragging them into position.

[Turtle91]

Looks like you got it figured out. However, for anyone else that might be wondering how to do this:

1) Rename the file extension from .epub to .zip
2) Open up the zip file and navigate to the .opf file
3) Change the <package version="3.0" ...> to version="2.0"
4) Save the zip
5) Rename the file extension from .zip to .epub
6) Open with your epub editor of choice and remove any other ePub3 specific tags that you don't wish to keep. i.e. <section></section>


You can create a basic ePub3 (one that doesn't use all the extra media features) and it will be readable in most of your larger devices/apps. ePub3 is the successor to ePub2 (at least until a newer version comes out) and more devices/apps are supporting those files. I dare to say that all of the current devices/apps still support ePub2 so that's why the majority of ePubs are still made in the version 2 format. If your target audience supports ePub3, then there really isn't a reason to avoid ePub3...it doesn't hurt anything...other than, maybe the sensibilities of a certain individual here on MR.

[SigilBear]

Originally Posted by Turtle91

If your target audience supports ePub3, then there really isn't a reason to avoid ePub3...it doesn't hurt anything...other than, maybe the sensibilities of a certain individual here on MR.

That's what I was thinking - make one version for a general audience and a more fully featured version for the Apple crowd, or any other device that might support it. I'm thinking of embedding some audio files in one book, and it sounds like Epub 2.0 doesn't support that.

[stumped]

Originally Posted by DiapDealer

Actually, no they're not "correct". A fairly decent chunk of the commercial epubs i buy and read these days are epub3.

To the OP: there is no automated way from epub3 back to epub2. Not with Sigil anyway...

I did it simply by running an epub to epub conversion in calibre.
epub3 IN, epub2 OUT, easy peasy, all on default settings
{ because I could not perform some sigil edit in an epub 3 source, I tried the above & it worked 1st time. I was able to edit the output file which sigil reported as being epub 2 }

[DiapDealer]

Originally Posted by stumped

( because I could not perform some sigil edit in an epub 3 source, I tried the above & it worked 1st time. I was able to edit the output file which sigil reported as being epub 2 }

I'm assuming the Sigil edit you could't make was changing the OPF's package version attribute from 3.0 to 2.0? Because that's frankly the only portion of the source Sigil won't allow you to edit manually (in any kind of epub).

If you're happy with the outcome, that's all that matters. Just know that a full calibre epub to epub conversion to go from 3 to 2 is a pretty drastic solution (from a volume-of-code altered standpoint). Especially if the ultimate goal is to get the epub into Sigil for editing. Most commercial epub3s can be manually converted fairly simply with Turtle91's above described procedure. With something like 7Zip, you can even edit the OPF within the epub archive and skip all the renaming unzipping/rezipping.

I'll see if I can't resurrect my input plugin that fixed opfs that incorrectly had 1.0 package versions and adapt it to change the 3.0 to 2.0. It won't automatically convert an epub3 to epub2 entirely, but it should get one into Sigil in an editable state where the rest can be done manually.

[Terisa de morgan]

Originally Posted by DiapDealer

I'm assuming the Sigil edit you could't make was changing the OPF's package version attribute from 3.0 to 2.0? Because that's frankly the only portion of the source Sigil won't allow you to edit manually (in any kind of epub).

@DiapDealer, I do this as a routine when the warning about nav.xhtml appears in calibre editor (plain epub, really). Is there any secondary effect that you know?

[JSWolf]

I do change ePub 3 to ePub 2. I use Notepad++ or Calibre's editor to do so. It's not difficult to do so. It means the ePub I end up with is more compatible overall. These eBooks do not need any ePub 3 specific features. Making them ePub 3 is silly. It just causes code bloat. i prefer to have the simplest code possible to do the job.

[DiapDealer]

Originally Posted by Terisa de morgan

@DiapDealer, I do this as a routine when the warning about nav.xhtml appears in calibre editor (plain epub, really). Is there any secondary effect that you know?

Do you mean effects from changing the package version from 3.0 to 2.0? Not that I know of (not directly anyway). Calibre's editor is actually another viable option for easily changing the package vesrion from 3 to 2. It's up to you whether finishing the "conversion" in Sigil or calibre's editor makes mores sense. In Sigil, running the epub2 gui metadata editor on an opf that was still primarily epub3 could end up with unforseen results, but I tend to edit the metadata in the opf manually in those situations anyway.

But then I don't do a lot of EPUB3 to EPUB2 conversions these days. Quite the opposite, in fact. I prefer the EPUB3 renderer in the Bookari reading app, so if the books I buy aren't already EPUB3, I tend to use Sigil's Epub3-itizer plugin to make them that way.

[stumped]

Originally Posted by DiapDealer

I'm assuming the Sigil edit you could't make was changing the OPF's package version attribute from 3.0 to 2.0? Because that's frankly the only portion of the source Sigil won't allow you to edit manually (in any kind of epub).

No it was NOT that. it was something I routinely do before reading, like removing unwanted epigraph / dedication / etc front pages..

I had not even realised it was epub3 until I looked into why the operation was not being allowed...
it's been a while but I am pretty sure it would not let me delete a specific xhtml file from the left hand list, while in epub3, and the error message was something about operation not allowed. I remember googling that for a clue...
I don't think I have an epub3 source to hand, else I'd try to replicate it for you....
....update: I did keep a copy. i wanted to delete toc.xtml from the top of the left window files list, expecting the "real" toc to be elsewhere in the epub (i.e. as toc.ncx at the bottom of that list ), and I got " the nav document cannot be removed"...
is there a difference in where the toc is usually placed & how it is named, between e2 & e3 or was that something specific to this source. Sigil, when operating on epub2 , allows delete/ rename etc... for anything in that left window file list ?

[Doitsu]

Originally Posted by JSWolf

I do change ePub 3 to ePub 2. I use Notepad++ or Calibre's editor to do so.

IMHO, that's a lot of extra work with little benefit. Even the ancient ADE 1.7 app opens epub2 compatible epub3 books without any problems, because fully epub2-compliant reading apps are supposed to ignore tags and attributes that they don't support. (You're more likely to encounter ADE problems with epub2 books if a CSS file contains rules that ADE doesn't like.)

And should you encounter a commercial epub3 book without an NCX file, you can easily add one with Sigil (Tools > Epub3 Tools > Generate NCX from Nav).