The pubdate attribute is not valid for modern HTML(5).

The h-entry microformat describes an alternative way to achieve the same thing: a dt-published class name.

Patch: https://github.com/jmtd/ikiwiki/commit/a137103d3004cc8cec42459205684ec48af0ca11

Available in a git repository branch.
Branch: jon/html5-no-pubdate-attribute
Author: Jon

Jon, 2020-10-06