diff --git a/homeassistant/components/frontend/__init__.py b/homeassistant/components/frontend/__init__.py
index 224970499f3..ba09e60b742 100644
--- a/homeassistant/components/frontend/__init__.py
+++ b/homeassistant/components/frontend/__init__.py
@@ -9,6 +9,7 @@ import hashlib
 import json
 import logging
 import os
+from urllib.parse import urlparse
 
 from aiohttp import web
 import voluptuous as vol
@@ -21,21 +22,19 @@ from homeassistant.const import CONF_NAME, EVENT_THEMES_UPDATED
 from homeassistant.core import callback
 from homeassistant.loader import bind_hass
 
-REQUIREMENTS = ['home-assistant-frontend==20171106.0']
+REQUIREMENTS = ['home-assistant-frontend==20171110.0']
 
 DOMAIN = 'frontend'
-DEPENDENCIES = ['api', 'websocket_api']
+DEPENDENCIES = ['api', 'websocket_api', 'http']
 
-URL_PANEL_COMPONENT = '/frontend/panels/{}.html'
 URL_PANEL_COMPONENT_FP = '/frontend/panels/{}-{}.html'
 
-POLYMER_PATH = os.path.join(os.path.dirname(__file__),
-                            'home-assistant-polymer/')
-FINAL_PATH = os.path.join(POLYMER_PATH, 'final')
-
 CONF_THEMES = 'themes'
 CONF_EXTRA_HTML_URL = 'extra_html_url'
 CONF_FRONTEND_REPO = 'development_repo'
+CONF_JS_VERSION = 'javascript_version'
+JS_DEFAULT_OPTION = 'es5'
+JS_OPTIONS = ['es5', 'latest', 'auto']
 
 DEFAULT_THEME_COLOR = '#03A9F4'
 
@@ -61,6 +60,7 @@ for size in (192, 384, 512, 1024):
 
 DATA_FINALIZE_PANEL = 'frontend_finalize_panel'
 DATA_PANELS = 'frontend_panels'
+DATA_JS_VERSION = 'frontend_js_version'
 DATA_EXTRA_HTML_URL = 'frontend_extra_html_url'
 DATA_THEMES = 'frontend_themes'
 DATA_DEFAULT_THEME = 'frontend_default_theme'
@@ -68,8 +68,6 @@ DEFAULT_THEME = 'default'
 
 PRIMARY_COLOR = 'primary-color'
 
-# To keep track we don't register a component twice (gives a warning)
-# _REGISTERED_COMPONENTS = set()
 _LOGGER = logging.getLogger(__name__)
 
 CONFIG_SCHEMA = vol.Schema({
@@ -80,6 +78,8 @@ CONFIG_SCHEMA = vol.Schema({
         }),
         vol.Optional(CONF_EXTRA_HTML_URL):
             vol.All(cv.ensure_list, [cv.string]),
+        vol.Optional(CONF_JS_VERSION, default=JS_DEFAULT_OPTION):
+            vol.In(JS_OPTIONS)
     }),
 }, extra=vol.ALLOW_EXTRA)
 
@@ -102,8 +102,9 @@ class AbstractPanel:
     # Title to show in the sidebar (optional)
     sidebar_title = None
 
-    # Url to the webcomponent
-    webcomponent_url = None
+    # Url to the webcomponent (depending on JS version)
+    webcomponent_url_es5 = None
+    webcomponent_url_latest = None
 
     # Url to show the panel in the frontend
     frontend_url_path = None
@@ -135,16 +136,20 @@ class AbstractPanel:
             'get', '/{}/{{extra:.+}}'.format(self.frontend_url_path),
             index_view.get)
 
-    def as_dict(self):
+    def to_response(self, hass, request):
         """Panel as dictionary."""
-        return {
+        result = {
             'component_name': self.component_name,
             'icon': self.sidebar_icon,
             'title': self.sidebar_title,
-            'url': self.webcomponent_url,
             'url_path': self.frontend_url_path,
             'config': self.config,
         }
+        if _is_latest(hass.data[DATA_JS_VERSION], request):
+            result['url'] = self.webcomponent_url_latest
+        else:
+            result['url'] = self.webcomponent_url_es5
+        return result
 
 
 class BuiltInPanel(AbstractPanel):
@@ -170,15 +175,19 @@ class BuiltInPanel(AbstractPanel):
 
         if frontend_repository_path is None:
             import hass_frontend
+            import hass_frontend_es5
 
-            self.webcomponent_url = \
-                '/static/panels/ha-panel-{}-{}.html'.format(
+            self.webcomponent_url_latest = \
+                '/frontend_latest/panels/ha-panel-{}-{}.html'.format(
                     self.component_name,
                     hass_frontend.FINGERPRINTS[panel_path])
-
+            self.webcomponent_url_es5 = \
+                '/frontend_es5/panels/ha-panel-{}-{}.html'.format(
+                    self.component_name,
+                    hass_frontend_es5.FINGERPRINTS[panel_path])
         else:
             # Dev mode
-            self.webcomponent_url = \
+            self.webcomponent_url_es5 = self.webcomponent_url_latest = \
                 '/home-assistant-polymer/panels/{}/ha-panel-{}.html'.format(
                     self.component_name, self.component_name)
 
@@ -208,18 +217,20 @@ class ExternalPanel(AbstractPanel):
         """
         try:
             if self.md5 is None:
-                yield from hass.async_add_job(_fingerprint, self.path)
+                self.md5 = yield from hass.async_add_job(
+                    _fingerprint, self.path)
         except OSError:
             _LOGGER.error('Cannot find or access %s at %s',
                           self.component_name, self.path)
             hass.data[DATA_PANELS].pop(self.frontend_url_path)
+            return
 
-        self.webcomponent_url = \
+        self.webcomponent_url_es5 = self.webcomponent_url_latest = \
             URL_PANEL_COMPONENT_FP.format(self.component_name, self.md5)
 
         if self.component_name not in self.REGISTERED_COMPONENTS:
             hass.http.register_static_path(
-                self.webcomponent_url, self.path,
+                self.webcomponent_url_latest, self.path,
                 # if path is None, we're in prod mode, so cache static assets
                 frontend_repository_path is None)
             self.REGISTERED_COMPONENTS.add(self.component_name)
@@ -281,31 +292,50 @@ def async_setup(hass, config):
 
     repo_path = conf.get(CONF_FRONTEND_REPO)
     is_dev = repo_path is not None
+    hass.data[DATA_JS_VERSION] = js_version = conf.get(CONF_JS_VERSION)
 
     if is_dev:
         hass.http.register_static_path(
             "/home-assistant-polymer", repo_path, False)
         hass.http.register_static_path(
             "/static/translations",
-            os.path.join(repo_path, "build/translations"), False)
-        sw_path = os.path.join(repo_path, "build/service_worker.js")
+            os.path.join(repo_path, "build-translations"), False)
+        sw_path_es5 = os.path.join(repo_path, "build-es5/service_worker.js")
+        sw_path_latest = os.path.join(repo_path, "build/service_worker.js")
         static_path = os.path.join(repo_path, 'hass_frontend')
+        frontend_es5_path = os.path.join(repo_path, 'build-es5')
+        frontend_latest_path = os.path.join(repo_path, 'build')
     else:
         import hass_frontend
-        frontend_path = hass_frontend.where()
-        sw_path = os.path.join(frontend_path, "service_worker.js")
-        static_path = frontend_path
+        import hass_frontend_es5
+        sw_path_es5 = os.path.join(hass_frontend_es5.where(),
+                                   "service_worker.js")
+        sw_path_latest = os.path.join(hass_frontend.where(),
+                                      "service_worker.js")
+        # /static points to dir with files that are JS-type agnostic.
+        # ES5 files are served from /frontend_es5.
+        # ES6 files are served from /frontend_latest.
+        static_path = hass_frontend.where()
+        frontend_es5_path = hass_frontend_es5.where()
+        frontend_latest_path = static_path
 
-    hass.http.register_static_path("/service_worker.js", sw_path, False)
+    hass.http.register_static_path(
+        "/service_worker_es5.js", sw_path_es5, False)
+    hass.http.register_static_path(
+        "/service_worker.js", sw_path_latest, False)
     hass.http.register_static_path(
         "/robots.txt", os.path.join(static_path, "robots.txt"), not is_dev)
     hass.http.register_static_path("/static", static_path, not is_dev)
+    hass.http.register_static_path(
+        "/frontend_latest", frontend_latest_path, not is_dev)
+    hass.http.register_static_path(
+        "/frontend_es5", frontend_es5_path, not is_dev)
 
     local = hass.config.path('www')
     if os.path.isdir(local):
         hass.http.register_static_path("/local", local, not is_dev)
 
-    index_view = IndexView(is_dev)
+    index_view = IndexView(is_dev, js_version)
     hass.http.register_view(index_view)
 
     @asyncio.coroutine
@@ -405,7 +435,7 @@ class IndexView(HomeAssistantView):
     requires_auth = False
     extra_urls = ['/states', '/states/{extra}']
 
-    def __init__(self, use_repo):
+    def __init__(self, use_repo, js_option):
         """Initialize the frontend view."""
         from jinja2 import FileSystemLoader, Environment
 
@@ -416,27 +446,37 @@ class IndexView(HomeAssistantView):
                 os.path.join(os.path.dirname(__file__), 'templates/')
             )
         )
+        self.js_option = js_option
 
     @asyncio.coroutine
     def get(self, request, extra=None):
         """Serve the index view."""
         hass = request.app['hass']
+        latest = _is_latest(self.js_option, request)
+        compatibility_url = None
 
         if self.use_repo:
-            core_url = '/home-assistant-polymer/build/core.js'
-            compatibility_url = \
-                '/home-assistant-polymer/build/compatibility.js'
+            core_url = '/home-assistant-polymer/{}/core.js'.format(
+                'build' if latest else 'build-es5')
             ui_url = '/home-assistant-polymer/src/home-assistant.html'
             icons_fp = ''
             icons_url = '/static/mdi.html'
         else:
+            if latest:
+                import hass_frontend
+                core_url = '/frontend_latest/core-{}.js'.format(
+                    hass_frontend.FINGERPRINTS['core.js'])
+                ui_url = '/frontend_latest/frontend-{}.html'.format(
+                    hass_frontend.FINGERPRINTS['frontend.html'])
+            else:
+                import hass_frontend_es5
+                core_url = '/frontend_es5/core-{}.js'.format(
+                    hass_frontend_es5.FINGERPRINTS['core.js'])
+                compatibility_url = '/frontend_es5/compatibility-{}.js'.format(
+                    hass_frontend_es5.FINGERPRINTS['compatibility.js'])
+                ui_url = '/frontend_es5/frontend-{}.html'.format(
+                    hass_frontend_es5.FINGERPRINTS['frontend.html'])
             import hass_frontend
-            core_url = '/static/core-{}.js'.format(
-                hass_frontend.FINGERPRINTS['core.js'])
-            compatibility_url = '/static/compatibility-{}.js'.format(
-                hass_frontend.FINGERPRINTS['compatibility.js'])
-            ui_url = '/static/frontend-{}.html'.format(
-                hass_frontend.FINGERPRINTS['frontend.html'])
             icons_fp = '-{}'.format(hass_frontend.FINGERPRINTS['mdi.html'])
             icons_url = '/static/mdi{}.html'.format(icons_fp)
 
@@ -447,8 +487,10 @@ class IndexView(HomeAssistantView):
 
         if panel == 'states':
             panel_url = ''
+        elif latest:
+            panel_url = hass.data[DATA_PANELS][panel].webcomponent_url_latest
         else:
-            panel_url = hass.data[DATA_PANELS][panel].webcomponent_url
+            panel_url = hass.data[DATA_PANELS][panel].webcomponent_url_es5
 
         no_auth = 'true'
         if hass.config.api.api_password and not is_trusted_ip(request):
@@ -468,7 +510,10 @@ class IndexView(HomeAssistantView):
             panel_url=panel_url, panels=hass.data[DATA_PANELS],
             dev_mode=self.use_repo,
             theme_color=MANIFEST_JSON['theme_color'],
-            extra_urls=hass.data[DATA_EXTRA_HTML_URL])
+            extra_urls=hass.data[DATA_EXTRA_HTML_URL],
+            latest=latest,
+            service_worker_name='/service_worker.js' if latest else
+            '/service_worker_es5.js')
 
         return web.Response(text=resp, content_type='text/html')
 
@@ -509,3 +554,20 @@ def _fingerprint(path):
     """Fingerprint a file."""
     with open(path) as fil:
         return hashlib.md5(fil.read().encode('utf-8')).hexdigest()
+
+
+def _is_latest(js_option, request):
+    """
+    Return whether we should serve latest untranspiled code.
+
+    Set according to user's preference and URL override.
+    """
+    if request is None:
+        return js_option == 'latest'
+    latest_in_query = 'latest' in request.query or (
+        request.headers.get('Referer') and
+        'latest' in urlparse(request.headers['Referer']).query)
+    es5_in_query = 'es5' in request.query or (
+        request.headers.get('Referer') and
+        'es5' in urlparse(request.headers['Referer']).query)
+    return latest_in_query or (not es5_in_query and js_option == 'latest')
diff --git a/homeassistant/components/frontend/templates/index.html b/homeassistant/components/frontend/templates/index.html
index c941fbc15ae..ae030a5d026 100644
--- a/homeassistant/components/frontend/templates/index.html
+++ b/homeassistant/components/frontend/templates/index.html
@@ -78,11 +78,11 @@
         <a href='/'>TRY AGAIN</a>
       </div>
     </div>
-    <home-assistant icons='{{ icons }}'></home-assistant>
-    {# <script src='/static/home-assistant-polymer/build/_demo_data_compiled.js'></script> #}
+    <home-assistant></home-assistant>
+    {# <script src='/static/home-assistant-polymer/build/_demo_data_compiled.js'></script> -#}
+    {% if not latest -%}
     <script>
-      var compatibilityRequired = (
-        typeof Object.assign != 'function');
+      var compatibilityRequired = (typeof Object.assign != 'function');
       if (compatibilityRequired) {
         var e = document.createElement('script');
         e.onerror = initError;
@@ -90,10 +90,11 @@
         document.head.appendChild(e);
       }
     </script>
+    {% endif -%}
     <script src='{{ core_url }}'></script>
-    {% if not dev_mode %}
-    <script src='/static/custom-elements-es5-adapter.js'></script>
-    {% endif %}
+    {% if not dev_mode and not latest -%}
+    <script src='/frontend_es5/custom-elements-es5-adapter.js'></script>
+    {% endif -%}
     <script>
       var webComponentsSupported = (
         'customElements' in window &&
@@ -105,6 +106,11 @@
         e.src = '/static/webcomponents-lite.js';
         document.head.appendChild(e);
       }
+      if ('serviceWorker' in navigator) {
+        window.addEventListener('load', function () {
+          navigator.serviceWorker.register('{{ service_worker_name }}');
+        });
+      }
     </script>
     <link rel='import' href='{{ ui_url }}' onerror='initError()'>
     {% if panel_url -%}
diff --git a/homeassistant/components/http/__init__.py b/homeassistant/components/http/__init__.py
index 659fd026bb8..17ceccfd218 100644
--- a/homeassistant/components/http/__init__.py
+++ b/homeassistant/components/http/__init__.py
@@ -262,7 +262,6 @@ class HomeAssistantWSGI(object):
                 resource = CachingStaticResource
             else:
                 resource = web.StaticResource
-
             self.app.router.register_resource(resource(url_path, path))
             return
 
diff --git a/homeassistant/components/http/static.py b/homeassistant/components/http/static.py
index c2576358f59..c9b094e3f2e 100644
--- a/homeassistant/components/http/static.py
+++ b/homeassistant/components/http/static.py
@@ -65,7 +65,8 @@ class CachingFileResponse(FileResponse):
 @asyncio.coroutine
 def staticresource_middleware(request, handler):
     """Middleware to strip out fingerprint from fingerprinted assets."""
-    if not request.path.startswith('/static/'):
+    path = request.path
+    if not path.startswith('/static/') and not path.startswith('/frontend'):
         return handler(request)
 
     fingerprinted = _FINGERPRINT.match(request.match_info['filename'])
diff --git a/homeassistant/components/websocket_api.py b/homeassistant/components/websocket_api.py
index e9f567c04d3..a1fb0ca9cac 100644
--- a/homeassistant/components/websocket_api.py
+++ b/homeassistant/components/websocket_api.py
@@ -202,15 +202,16 @@ class WebsocketAPIView(HomeAssistantView):
     def get(self, request):
         """Handle an incoming websocket connection."""
         # pylint: disable=no-self-use
-        return ActiveConnection(request.app['hass']).handle(request)
+        return ActiveConnection(request.app['hass'], request).handle()
 
 
 class ActiveConnection:
     """Handle an active websocket client connection."""
 
-    def __init__(self, hass):
+    def __init__(self, hass, request):
         """Initialize an active connection."""
         self.hass = hass
+        self.request = request
         self.wsock = None
         self.event_listeners = {}
         self.to_write = asyncio.Queue(maxsize=MAX_PENDING_MSG, loop=hass.loop)
@@ -259,8 +260,9 @@ class ActiveConnection:
         self._writer_task.cancel()
 
     @asyncio.coroutine
-    def handle(self, request):
+    def handle(self):
         """Handle the websocket connection."""
+        request = self.request
         wsock = self.wsock = web.WebSocketResponse()
         yield from wsock.prepare(request)
         self.debug("Connected")
@@ -350,7 +352,7 @@ class ActiveConnection:
             if wsock.closed:
                 self.debug("Connection closed by client")
             else:
-                self.log_error("Unexpected TypeError", msg)
+                _LOGGER.exception("Unexpected TypeError: %s", msg)
 
         except ValueError as err:
             msg = "Received invalid JSON"
@@ -483,9 +485,14 @@ class ActiveConnection:
         Async friendly.
         """
         msg = GET_PANELS_MESSAGE_SCHEMA(msg)
+        panels = {
+            panel:
+            self.hass.data[frontend.DATA_PANELS][panel].to_response(
+                self.hass, self.request)
+            for panel in self.hass.data[frontend.DATA_PANELS]}
 
         self.to_write.put_nowait(result_message(
-            msg['id'], self.hass.data[frontend.DATA_PANELS]))
+            msg['id'], panels))
 
     def handle_ping(self, msg):
         """Handle ping command.
diff --git a/requirements_all.txt b/requirements_all.txt
index 9b7bb4b3cde..782e9930daa 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -330,7 +330,7 @@ hipnotify==1.0.8
 holidays==0.8.1
 
 # homeassistant.components.frontend
-home-assistant-frontend==20171106.0
+home-assistant-frontend==20171110.0
 
 # homeassistant.components.camera.onvif
 http://github.com/tgaugry/suds-passworddigest-py3/archive/86fc50e39b4d2b8997481967d6a7fe1c57118999.zip#suds-passworddigest-py3==0.1.2a
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 9f45cc4516e..083c2792db2 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -74,7 +74,7 @@ hbmqtt==0.8
 holidays==0.8.1
 
 # homeassistant.components.frontend
-home-assistant-frontend==20171106.0
+home-assistant-frontend==20171110.0
 
 # homeassistant.components.influxdb
 # homeassistant.components.sensor.influxdb
diff --git a/tests/components/test_frontend.py b/tests/components/test_frontend.py
index 1b034cfe940..3d8d2b62a2b 100644
--- a/tests/components/test_frontend.py
+++ b/tests/components/test_frontend.py
@@ -52,7 +52,7 @@ def test_frontend_and_static(mock_http_client):
 
     # Test we can retrieve frontend.js
     frontendjs = re.search(
-        r'(?P<app>\/static\/frontend-[A-Za-z0-9]{32}.html)', text)
+        r'(?P<app>\/frontend_es5\/frontend-[A-Za-z0-9]{32}.html)', text)
 
     assert frontendjs is not None
     resp = yield from mock_http_client.get(frontendjs.groups(0)[0])
@@ -63,6 +63,10 @@ def test_frontend_and_static(mock_http_client):
 @asyncio.coroutine
 def test_dont_cache_service_worker(mock_http_client):
     """Test that we don't cache the service worker."""
+    resp = yield from mock_http_client.get('/service_worker_es5.js')
+    assert resp.status == 200
+    assert 'cache-control' not in resp.headers
+
     resp = yield from mock_http_client.get('/service_worker.js')
     assert resp.status == 200
     assert 'cache-control' not in resp.headers
diff --git a/tests/components/test_panel_iframe.py b/tests/components/test_panel_iframe.py
index 00c824418be..9a56479c469 100644
--- a/tests/components/test_panel_iframe.py
+++ b/tests/components/test_panel_iframe.py
@@ -33,7 +33,7 @@ class TestPanelIframe(unittest.TestCase):
                     'panel_iframe': conf
                 })
 
-    @patch.dict('hass_frontend.FINGERPRINTS',
+    @patch.dict('hass_frontend_es5.FINGERPRINTS',
                 {'panels/ha-panel-iframe.html': 'md5md5'})
     def test_correct_config(self):
         """Test correct config."""
@@ -55,20 +55,20 @@ class TestPanelIframe(unittest.TestCase):
 
         panels = self.hass.data[frontend.DATA_PANELS]
 
-        assert panels.get('router').as_dict() == {
+        assert panels.get('router').to_response(self.hass, None) == {
             'component_name': 'iframe',
             'config': {'url': 'http://192.168.1.1'},
             'icon': 'mdi:network-wireless',
             'title': 'Router',
-            'url': '/static/panels/ha-panel-iframe-md5md5.html',
+            'url': '/frontend_es5/panels/ha-panel-iframe-md5md5.html',
             'url_path': 'router'
         }
 
-        assert panels.get('weather').as_dict() == {
+        assert panels.get('weather').to_response(self.hass, None) == {
             'component_name': 'iframe',
             'config': {'url': 'https://www.wunderground.com/us/ca/san-diego'},
             'icon': 'mdi:weather',
             'title': 'Weather',
-            'url': '/static/panels/ha-panel-iframe-md5md5.html',
+            'url': '/frontend_es5/panels/ha-panel-iframe-md5md5.html',
             'url_path': 'weather',
         }
diff --git a/tests/components/test_websocket_api.py b/tests/components/test_websocket_api.py
index c310b0d5445..8b6c7494214 100644
--- a/tests/components/test_websocket_api.py
+++ b/tests/components/test_websocket_api.py
@@ -290,7 +290,7 @@ def test_get_panels(hass, websocket_client):
     """Test get_panels command."""
     yield from hass.components.frontend.async_register_built_in_panel(
         'map', 'Map', 'mdi:account-location')
-
+    hass.data[frontend.DATA_JS_VERSION] = 'es5'
     websocket_client.send_json({
         'id': 5,
         'type': wapi.TYPE_GET_PANELS,
@@ -300,8 +300,14 @@ def test_get_panels(hass, websocket_client):
     assert msg['id'] == 5
     assert msg['type'] == wapi.TYPE_RESULT
     assert msg['success']
-    assert msg['result'] == {url: panel.as_dict() for url, panel
-                             in hass.data[frontend.DATA_PANELS].items()}
+    assert msg['result'] == {'map': {
+        'component_name': 'map',
+        'url_path': 'map',
+        'config': None,
+        'url': None,
+        'icon': 'mdi:account-location',
+        'title': 'Map',
+    }}
 
 
 @asyncio.coroutine