create /unsupported/outdated version of the /unsupported page

frontend/src/common.js

@@ -16,7 +16,7 @@ gcmCompliant().catch(err => {
   sendEvent(isSender ? 'sender' : 'recipient', 'unsupported', {
     cd6: err
   }).then(() => {
-    location.replace('/unsupported');
+    location.replace('/unsupported/gcm');
   });
 });
 
@@ -25,6 +25,6 @@ if (navigator.userAgent.toLowerCase().indexOf('firefox') > -1 &&
     sendEvent(isSender ? 'sender' : 'recipient', 'unsupported', {
       cd6: new Error('Firefox is outdated.')
     }).then(() => {
-      location.replace('/unsupported');
+      location.replace('/unsupported/outdated');
     });
 }

public/locales/en-US/send.ftl

@@ -67,6 +67,8 @@ expiredPageHeader = This link has expired or never existed in the first place!
 notSupportedHeader = Your browser is not supported.
 // Firefox Send is a brand name and should not be localized.
 notSupportedDetail = Unfortunately this browser does not support the web technology that powers Firefox Send. You’ll need to try another browser. We recommend Firefox!
+notSupportedOutdatedDetail = Unfortunately this version of Firefox does not support the web technology that powers Firefox Send. You’ll need to update your browser.
+updateFirefox = Update Firefox
 downloadFirefoxButtonSub = Free Download
 uploadedFile = File
 copyFileList = Copy URL

public/main.css

@@ -517,13 +517,13 @@ tbody {
   margin: 0 auto 23px;
 }
 
-#firefox-logo {
+.firefox-logo {
   width: 70px;
 }
 
-#dl-firefox {
+#dl-firefox,
+#update-firefox {
   margin-bottom: 181px;
-  width: 260px;
   height: 80px;
   background: #12bc00;
   border-radius: 3px;
@@ -538,14 +538,15 @@ tbody {
   justify-content: center;
   align-items: center;
   line-height: 1;
+  padding: 0 25px;
 }
 
-#dl-firefox-text {
+.unsupported-button-text {
   text-align: left;
   margin-left: 20.4px;
 }
 
-#dl-firefox-text > span {
+.unsupported-button-text > span {
   font-family: 'Fira Sans';
   font-weight: 300;
   font-size: 18px;

server/server.js

@@ -96,8 +96,11 @@ app.get('/', (req, res) => {
   res.render('index');
 });
 
-app.get('/unsupported', (req, res) => {
+app.get('/unsupported/:reason', (req, res) => {
-  res.render('unsupported');
+  const outdated = req.params.reason === 'outdated'? true : false;
+  res.render('unsupported', {
+    outdated: outdated
+  });
 });
 
 app.get('/legal', (req, res) => {

views/unsupported.handlebars

@@ -1,11 +1,19 @@
 <div id="unsupported-browser">
   <div class="title" data-l10n-id="notSupportedHeader"></div>
+  {{#if outdated}}
+    <div class="description" data-l10n-id="notSupportedOutdatedDetail"></div>
+    <a id="update-firefox" href="https://support.mozilla.org/az/kb/update-firefox-latest-version">
+      <img src="/resources/firefox_logo-only.svg" class="firefox-logo" alt="Firefox"/>
+      <div class="unsupported-button-text" data-l10n-id="updateFirefox"></div>
+    </a>
+  {{else}}
     <div class="description" data-l10n-id="notSupportedDetail"></div>
     <a id="dl-firefox" href="https://www.mozilla.org/firefox/new/?scene=2" target="_blank">
-    <img src="/resources/firefox_logo-only.svg" id="firefox-logo" alt="Firefox"/>
+      <img src="/resources/firefox_logo-only.svg" class="firefox-logo" alt="Firefox"/>
-    <div id="dl-firefox-text">Firefox<br>
+      <div class="unsupported-button-text">Firefox<br>
         <span data-l10n-id="downloadFirefoxButtonSub"></span>
       </div>
     </a>
+  {{/if}}
   <div class="unsupported-description" data-l10n-id="uploadPageExplainer"></div>
 </div>