diff --git a/content/documentation/v1/_index.md b/content/documentation/v1/_index.md
index 337ff6288..4b0a6ff29 100644
--- a/content/documentation/v1/_index.md
+++ b/content/documentation/v1/_index.md
@@ -9,4 +9,10 @@ menu:
     weight: 2
 ---
 
+<div class="version-deprecation-notice">
+  <strong>Apache NiFi Version 1 is no longer maintained.</strong>
+  This documentation applies to NiFi 1.x. For the latest documentation, see
+  <a href="/components/">NiFi Version 2 Documentation</a>.
+</div>
+
 <iframe class="documentation-container" src="https://nifi.apache.org/docs/nifi-docs/"></iframe>
diff --git a/themes/nifi/static/css/main.css b/themes/nifi/static/css/main.css
index 9ab5101c0..ee41eec28 100644
--- a/themes/nifi/static/css/main.css
+++ b/themes/nifi/static/css/main.css
@@ -113,9 +113,35 @@ img.navbar-logo {
   height: calc(100vh - 100px);
 }
 
+.iframe-container:has(.version-deprecation-notice) {
+  display: flex;
+  flex-direction: column;
+}
+
 iframe.documentation-container {
   width: 100%;
   height: 100%;
+  flex: 1;
+}
+
+.version-deprecation-notice {
+  background-color: #fff3cd;
+  border: 1px solid #ffc107;
+  color: #664d03;
+  padding: 12px 24px;
+  font-size: 0.95rem;
+  line-height: 1.5;
+  text-align: center;
+}
+
+.version-deprecation-notice a {
+  color: #664d03;
+  font-weight: 600;
+  text-decoration: underline;
+}
+
+.version-deprecation-notice a:hover {
+  color: #3d2e02;
 }
 
 .hero .uk-grid {