diff --git a/library.json b/library.json
index 87bfaf66..6178106e 100644
--- a/library.json
+++ b/library.json
@@ -14,7 +14,7 @@
       "maintainer": true
     }
   ],
-  "version": "5.0.0",
+  "version": "5.1.0",
   "frameworks": ["espidf", "arduino"],
   "platforms": "espressif32",
   "dependencies": [
diff --git a/src/gridui_version.h b/src/gridui_version.h
index 128ddf67..86e7c7ea 100644
--- a/src/gridui_version.h
+++ b/src/gridui_version.h
@@ -1,3 +1,3 @@
 #pragma once
 
-#define RB_GRIDUI_VERSION 0x050000
+#define RB_GRIDUI_VERSION 0x050100
diff --git a/web/index.html b/web/index.html
index 506e7771..1161693c 100644
--- a/web/index.html
+++ b/web/index.html
@@ -48,13 +48,39 @@
         left: 0px;
         right: 0px;
       }
+
+      #captive-msg {
+        display: none;
+        margin: auto;
+        text-align: center;
+        padding: 16px;
+      }
+
+      #captive-link {
+        padding: 5px;
+        font-size: larger;
+      }
     </style>
   </head>
 
   <body id="body">
-    <div id="log" class="log-short"></div>
+    <div id="main-ui">
+      <div id="log" class="log-short"></div>
+
+      <div id="grid"></div>
+    </div>
 
-    <div id="grid"></div>
+    <div id="captive-msg">
+      <h2>Grid UI controls</h2>
+      <p>The GridUI controls do not work well in this limited captive portal browser.</p>
+      <div style="margin: 16px">
+        <a id="captive-link">[ Open in browser ]</a>
+      </div>
+      <p><i>If the link above does not work, please open <b id="captive-url"></b> in your normal web browser.</i></p>
+      <div style="margin-top: 48px">
+        <a href="javascript:void(0)" onclick="closeCaptivePortalNotice();">Show the controls anyway</a>
+      </div>
+    </div>
 
     <script src="combined.js"></script>
   </body>
diff --git a/web/js/99_footer.js b/web/js/99_footer.js
index db47cb8f..81f712e1 100644
--- a/web/js/99_footer.js
+++ b/web/js/99_footer.js
@@ -1,4 +1,15 @@
 window.addEventListener('load', function () {
+  // Detect captive portal and show message
+  var ua = window.navigator.userAgent;
+  if(ua.indexOf("; wv)") !== -1 && ua.indexOf("Chrome/") !== -1 && ua.indexOf("Version/") !== -1 && ua.indexOf("Android") !== -1) {
+    document.getElementById("main-ui").style.display = "none";
+    document.getElementById("captive-msg").style.display = "block";
+
+    document.getElementById("captive-url").innerText = window.location.origin;
+    document.getElementById("captive-link").href = "intent://" + window.location.hostname + "#Intent;scheme=http;end";
+    return;
+  }
+
   var man = new Manager('log', 'grid')
 
   // Detect whether we're running in RBController or just web browser
@@ -8,3 +19,8 @@ window.addEventListener('load', function () {
     man.start('ws://' + window.location.host, true)
   }
 })
+
+function closeCaptivePortalNotice() {
+  document.getElementById('main-ui').style.display = "block";
+  document.getElementById('captive-msg').style.display = 'none'
+}
