diff --git a/www/common/boot2.js b/www/common/boot2.js
index 487eb8ae6..ec3b3d7db 100644
--- a/www/common/boot2.js
+++ b/www/common/boot2.js
@@ -11,6 +11,16 @@ define([
         };
     }
 
+    // file encryption/decryption won't work if you don't have Array.fill
+    if (typeof(Array.prototype.fill) !== 'function') {
+        Array.prototype.fill = function (x) { // CRYPTPAD_SHIM
+            var i = 0;
+            var l = this.length;
+            for (;i < l; i++) { this[i] = x; }
+            return this;
+        };
+    }
+
     var failStore = function () {
         console.error(new Error('wut'));
         require(['jquery'], function ($) {
diff --git a/www/common/cryptpad-common.js b/www/common/cryptpad-common.js
index ef55f6f6b..f5bbbef55 100644
--- a/www/common/cryptpad-common.js
+++ b/www/common/cryptpad-common.js
@@ -209,15 +209,18 @@ define([
 
     common.isFeedbackAllowed = function () {
         try {
-            if (!getStore().getProxy().proxy.allowUserFeedback) { return; }
+            if (!getStore().getProxy().proxy.allowUserFeedback) { return false; }
             return true;
-        } catch (e) { return void console.error(e); }
+        } catch (e) {
+            console.error(e);
+            return false;
+        }
     };
     var feedback = common.feedback = function (action, force) {
+        if (!action) { return; }
         if (force !== true) {
-            if (!action) { return; }
             try {
-                if (!getStore().getProxy().proxy.allowUserFeedback) { return; }
+                if (!common.isFeedbackAllowed()) { return; }
             } catch (e) { return void console.error(e); }
         }
 
@@ -1951,10 +1954,15 @@ define([
                 feedback("NO_PROXIES");
             }
 
-            if (/CRYPTPAD_SHIM/.test(Array.isArray.toString())) {
+            var shimPattern = /CRYPTPAD_SHIM/;
+            if (shimPattern.test(Array.isArray.toString())) {
                 feedback("NO_ISARRAY");
             }
 
+            if (shimPattern.test(Array.prototype.fill.toString())) {
+                feedback("NO_ARRAYFILL");
+            }
+
             common.reportScreenDimensions();
             common.reportLanguage();