[BetterRed]

Originally Posted by halloleo

@BetterRead Thanks for the tip! Interesting!

So this means the published field is a custom column, right? Can I export them in the OPF file?

Yes, these screen shots should explain the relevant Preferences I'm using:





And here you see the result:



It suits me because I always use ISO (military) dates (and a 24 hour clock). Might not suit those who prefer other representations - e.g MMM.dd.yy.

This is what's written to the book folder\metadata.opf file and the content.opf file in the .epub file

<meta name="calibre:user_metadata:#part_date" content="{&quot;table&quot;: &quot;custom_column_61&quot;, &quot;column&quot;: &quot;value&quot;, &quot;datatype&quot;: &quot;text&quot;, &quot;is_multiple&quot;: null, &quot;kind&quot;: &quot;field&quot;, &quot;name&quot;: &quot;Partial Date&quot;, &quot;search_terms&quot;: [&quot;#part_date&quot;], &quot;label&quot;: &quot;part_date&quot;, &quot;colnum&quot;: 61, &quot;display&quot;: {&quot;use_decorations&quot;: 0, &quot;description&quot;: &quot;&quot;}, &quot;is_custom&quot;: true, &quot;is_category&quot;: true, &quot;link_column&quot;: &quot;value&quot;, &quot;category_sort&quot;: &quot;value&quot;, &quot;is_csp&quot;: false, &quot;is_editable&quot;: true, &quot;rec_index&quot;: 58, &quot;#value#&quot;: &quot;2008.05&quot;, &quot;#extra#&quot;: null, &quot;is_multiple2&quot;: {}}"/>

BR