# EPUBCheck OPF-053: date in nonstandard format, how to fix it

Source: https://epubcc.com/epubcheck/opf-053/ (updated 2026-11-04)

EPUBCheck OPF-053 is a warning message: “Date value "…" does not follow recommended syntax as per http://www.w3.org/TR/NOTE-datetime:….” A date in the metadata does not follow the recommended W3C date and time format, so some apps may not read it. EPUBCheck quotes the value and the reason.

- Official message (EPUBCheck 5.4.0): Date value "%1$s" does not follow recommended syntax as per http://www.w3.org/TR/NOTE-datetime:%2$s.
- Default severity: Warning

## Typical causes

- Dates written as text or in local formats, such as "March 2020" or "03/15/2020".
- A date with a time but no time zone, or extra text after the date.
- Metadata imported from a system that uses another date format.

## How to fix it

1. Find the date element EPUBCheck points to (usually dc:date).
2. Rewrite it as YYYY, YYYY-MM or YYYY-MM-DD, for example 2020-03-15.
3. If you include a time, use the full form with a time zone, such as 2020-03-15T10:00:00Z.

## When it's not this

If the value is not a real date at all, EPUBCheck reports OPF-054, an error.

## Sources

- EPUB 3.3, §5.5.3.2.4 The dc:date element: https://www.w3.org/TR/epub-33/#sec-opf-dcdate (read 2026-11-04)

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