diff --git a/layouts/blog/single.html b/layouts/blog/single.html
index 954ffb2..32bc6c0 100644
--- a/layouts/blog/single.html
+++ b/layouts/blog/single.html
@@ -18,6 +18,7 @@
     {{ partial "date.html" . }}
     {{ partial "reading_time.html" . }}
     {{ partial "tags/page.html" . }}
+    {{ partial "age_warning.html" . }}
     <!-- content -->
     <div class="e-content">
       {{ .Content }}
diff --git a/layouts/partials/age_warning.html b/layouts/partials/age_warning.html
new file mode 100644
index 0000000..5bdf79f
--- /dev/null
+++ b/layouts/partials/age_warning.html
@@ -0,0 +1,23 @@
+
+{{ 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 }}
+
+
+