diff --git a/appengine/src/com/google/android/chrometophone/server/SendServlet.java b/appengine/src/com/google/android/chrometophone/server/SendServlet.java
index bbeacce..6cb4581 100644
--- a/appengine/src/com/google/android/chrometophone/server/SendServlet.java
+++ b/appengine/src/com/google/android/chrometophone/server/SendServlet.java
@@ -52,12 +52,9 @@ public class SendServlet extends HttpServlet {
         resp.setContentType("text/plain");
 
         // Basic XSRF protection
-        if (req.getHeader("X-Extension") == null &&
-                req.getHeader("User-Agent").indexOf("Firefox") == -1) {  // TODO: Remove exception for Firefox
+        if (req.getHeader("X-Extension") == null) {
             resp.setStatus(400);
-            resp.getWriter().println(ERROR_STATUS + " You are using an old version of the extension that is no " +
-                    "longer supported. Please install v0.2 or later of the extension " +
-                    "from http://code.google.com/p/chrometophone.");
+            resp.getWriter().println(ERROR_STATUS + " - Please upgrade your extension");
             log.warning("Missing X-Extension header");
             resp.setStatus(400);
             return;