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EPUBCheck · XHTML content documents

EPUBCheck HTM-001: XML version is not 1.0

Updated:

EPUBCheck HTM-001 is an error message: “Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: ….” An XML file in the EPUB declares an XML version other than 1.0. EPUB requires every XML-based resource (XHTML chapters, the package document, the NCX, SVG images) to be a valid XML 1.0 document, and EPUBCheck names the version it found.

The official message

Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: %1$s.

Default severity
Error. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.
EPUBCheck version
5.4.0

%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.

Typical causes

  • An XML declaration that says version="1.1", written by an editor or an export tool that defaults to it.
  • A template copied from another XML project and reused for every chapter.

How to fix it

  1. Open the file EPUBCheck names (the message gives the path, line and column) in a text or EPUB editor such as Sigil, or unzip the EPUB and open it there.
  2. Change the first line to <?xml version="1.0" encoding="UTF-8"?>, or remove the XML declaration: without one, XML 1.0 and UTF-8 are assumed.
  3. If the tool that made the book writes 1.1 in every file, fix its template so the next export is right.
  4. Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.

When it's not this

If the declaration says 1.0 but the file is saved in UTF-16, that is HTM_058, not HTM-001.

Terms used here

Other HTM messages

  • HTM-003 External entities are not allowed in EPUB v3 documents. External entity declaration found: ….
  • HTM-004 Irregular DOCTYPE: found "…", expected "…".
  • HTM-007 Empty or whitespace-only value of attribute ssml:ph.
  • HTM-009 The DOCTYPE provided is obsolete or irregular and can be removed.
  • HTM-010 Namespace "…" is unusual for the prefix "epub".
  • HTM-011 Entity is undeclared.

Sources

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.

FAQ

What does EPUBCheck HTM-001 mean?

EPUBCheck HTM-001 is an error message: “Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: ….” An XML file in the EPUB declares an XML version other than 1.0. EPUB requires every XML-based resource (XHTML chapters, the package document, the NCX, SVG images) to be a valid XML 1.0 document, and EPUBCheck names the version it found.

Is HTM-001 an error?

HTM-001 is reported as error by default. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.