read.bib wrongly requires year field when date is valid

[HughParsonage]

biblatex advises bib entries use a date field, rather than year, but read.bib discards such entries. The following should be valid:

example.bib

@Article{newspaper,
    author = {Author Smith},
    title  = {Article title},
    date   = {2016-12-21},
    journal = {Newspaper name},
}

\documentclass{article}
\usepackage[style=authoryear]{biblatex}

\addbibresource{example.bib}

\begin{document}
\nocite{*}
\printbibliography
\end{document}