# EPUBCheck HTM-009: The DOCTYPE provided is obsolete or…

Source: https://epublab.com/epubcheck/htm-009/ (updated 2026-11-03)

EPUBCheck HTM-009 is an error message: “The DOCTYPE provided is obsolete or irregular and can be removed.” A document's DOCTYPE is obsolete or irregular and can simply be removed.

- Official message (EPUBCheck 5.4.0): The DOCTYPE provided is obsolete or irregular and can be removed.
- Default severity: Error

## Typical causes

- Old DOCTYPEs kept from earlier versions of the book.

## How to fix it

- Remove the DOCTYPE, or replace it with <!DOCTYPE html> in XHTML content documents.

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.