HTML or XHTML

[Barnes]

I prefer working with XHTML in my e-books, but I see a lot of HTML based EPUBs out there. So are there any good reasons to choose XHTML instead of HTML when creating EPUB 3 ebooks?

[Radu]

Hi,

There are two popular versions of EPUB, versions 2 and 3:
https://en.wikipedia.org/wiki/EPUB
Version 2 of EPUB uses from what I remember XHTML files valid according to the XHTML 1.1 specs.
Version 3 still requires XHTML, but it's more relaxed as to the XHTML version, Oxygen validates it with the XHTML 5 schema specification:
https://www.w3.org/publishing/epub3/epu ... #sec-xhtml

Regards,
Radu