diff --git a/docs/outdated-version.html b/docs/outdated-version.html
new file mode 100644
index 00000000..e698ed26
--- /dev/null
+++ b/docs/outdated-version.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>ODK Central</title>
+    <link rel="stylesheet" href="style.css">
+  </head>
+  <body>
+    <!-- this page is rendered in an iframe of size 600x200 -->
+    <div class="outdated-version">
+      <h1>You're using a significantly outdated version of ODK Central</h1>
+      <p>Upgrade now to protect your data and take advantage of the latest features. If you don't want to maintain Central, try <a href="https://getodk.org/#success-stories" target="_blank">ODK Cloud.</a></p>
+      <script defer src='https://static.cloudflareinsights.com/beacon.min.js' data-cf-beacon='{"token": "81f288331d6e4638be205e0e63388165"}'></script>
+    </div>
+  </body>
+</html>
diff --git a/docs/style.css b/docs/style.css
index d83feab7..3957dbb8 100644
--- a/docs/style.css
+++ b/docs/style.css
@@ -60,3 +60,11 @@ a:focus {
 .news-item a {
   margin-left: 82px;
 }
+
+.outdated-version h1 {
+  font-size: 30px;
+}
+
+.outdated-version p {
+  font-size: 18px;
+}
\ No newline at end of file
