{{ if and (not .Date.IsZero) .Site.Params.warnPostOlderThanXYears }}


    {{ $ageYears := div (sub now.Unix .Date.Unix) 31536000 }}

    {{ if .Lastmod }}
        {{ $ageYears := div (sub now.Unix .Lastmod.Unix) 31536000 }}
    {{ end }}

    {{ if gt $ageYears .Site.Params.warnPostOlderThanXYears }}
<div style="margin-top: 1rem; border: 1px solid black; padding: 1rem;">
    <em>Warning</em>: This post has not been modified
    for over {{ .Site.Params.warnPostOlderThanXYears }} years. For technical posts,
    make sure that it is still relevant.
</div>
    {{ end }}


{{ end }}