diff --git a/doc/extending/events.rst b/doc/extending/events.rst
index 2741bd421..90bcef511 100644
--- a/doc/extending/events.rst
+++ b/doc/extending/events.rst
@@ -736,16 +736,30 @@ this user is disabled).
 TopNotifications
 ================
 
-Let extensions add custom content into the top bar.
+Lets extensions subscribe to the global notification service (located
+inside the top bar).
 
 *Callback prototype*::
 
-  def callback(user): pass
+  def callback(user, include_all): pass
 
 * ``user`` is a ``User`` instance corresponding to the currently
   logged in user
+* ``include_all`` is a boolean indicating if empty notifications must
+  be included into the result or not
 
-Callbacks listening to this event must return a list of string.
+Callbacks listening to this event must return a list of dictionary,
+each dictionary containing at least the following entries::
+
+  {"id": "<notification entry ID>",
+   "url": "<associated URL>",
+   "text": "<text to display>"}
+
+If your notification needs a counter, you can specify it by adding the
+two following entries in the dictionary:
+
+  {"counter": <associated counter>,
+   "level": "<info|success|warning|error>"}
 
 UserLogin
 =========
diff --git a/modoboa/core/__init__.py b/modoboa/core/__init__.py
index ec4208b38..bd9ba2318 100644
--- a/modoboa/core/__init__.py
+++ b/modoboa/core/__init__.py
@@ -1,7 +1,12 @@
-from django.utils.translation import ugettext_lazy
+import os
+
+from django.core.urlresolvers import reverse
+from django.utils.translation import ugettext as _, ugettext_lazy
+
+from modoboa.core.utils import new_version_available
 from modoboa.lib import parameters, events
 
-base_events = [
+BASE_EVENTS = [
     "CanCreate",
 
     "AccountCreated",
@@ -51,7 +56,7 @@ def load_core_settings():
 
     parameters.register(GeneralParametersForm, ugettext_lazy("General"))
     parameters.register(UserSettings, ugettext_lazy("General"))
-    events.declare(base_events)
+    events.declare(BASE_EVENTS)
 
 
 @events.observe("ExtDisabled")
@@ -63,3 +68,20 @@ def unset_default_topredirection(extension):
     topredirection = parameters.get_admin("DEFAULT_TOP_REDIRECTION")
     if topredirection == extension.name:
         parameters.save_admin("DEFAULT_TOP_REDIRECTION", "core")
+
+
+@events.observe("TopNotifications")
+def check_for_new_version(user, include_all):
+    """
+    Check if a new version of Modoboa is available.
+    """
+    if not user.is_superuser:
+        return []
+    if new_version_available() is None:
+        return [{"id": "newversionavailable"}] if include_all else []
+    return [{
+        "id": "newversionavailable",
+        "url": reverse("admin_index") + "#info/",
+        "text": _("New Modoboa version available"),
+        "level": "info",
+    }]
diff --git a/modoboa/core/app_settings.py b/modoboa/core/app_settings.py
index 3b3a77df6..1b01fe34e 100644
--- a/modoboa/core/app_settings.py
+++ b/modoboa/core/app_settings.py
@@ -171,6 +171,19 @@ class GeneralParametersForm(parameters.AdminParametersForm):
 
     sep3 = SeparatorField(label=ugettext_lazy("Miscellaneous"))
 
+    top_notifications_check_interval = forms.IntegerField(
+        label=_("Top notifications check interval"),
+        initial=30,
+        help_text=_("Interval between two top notification checks")
+    )
+
+    check_new_versions = YesNoField(
+        label=ugettext_lazy("Check for new versions"),
+        initial="yes",
+        help_text=ugettext_lazy(
+            "Automatically checks if newer versions are available")
+    )
+
     log_maximum_age = forms.IntegerField(
         label=ugettext_lazy("Maximum log record age"),
         initial=365,
diff --git a/modoboa/core/commands/templates/settings.py.tpl b/modoboa/core/commands/templates/settings.py.tpl
index c0df35122..07e01a342 100644
--- a/modoboa/core/commands/templates/settings.py.tpl
+++ b/modoboa/core/commands/templates/settings.py.tpl
@@ -103,6 +103,18 @@ TEMPLATE_LOADERS = (
 #     'django.template.loaders.eggs.Loader',
 )
 
+TEMPLATE_CONTEXT_PROCESSORS = (
+    'django.contrib.auth.context_processors.auth',
+    'django.core.context_processors.debug',
+    'django.core.context_processors.i18n',
+    'django.core.context_processors.media',
+    'django.core.context_processors.static',
+    'django.core.context_processors.tz',
+    'django.contrib.messages.context_processors.messages',
+
+    'modoboa.core.context_processors.top_notifications',
+)
+
 MIDDLEWARE_CLASSES = (
     'django.middleware.common.CommonMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
@@ -174,6 +186,8 @@ SOUTH_TESTS_MIGRATE = False
 
 #DOVECOT_LOOKUP_PATH = ('/path/to/dovecot', )
 
+MODOBOA_API_URL = 'https://api.modoboa.org/1/'
+
 AUTHENTICATION_BACKENDS = (
     'modoboa.lib.authbackends.SimpleBackend',
 )
diff --git a/modoboa/core/context_processors.py b/modoboa/core/context_processors.py
new file mode 100644
index 000000000..218d6bf6e
--- /dev/null
+++ b/modoboa/core/context_processors.py
@@ -0,0 +1,18 @@
+"""
+Custom context processors.
+"""
+from modoboa.lib import events, parameters
+
+
+def top_notifications(request):
+    """
+    A context processor to include top notifications.
+    """
+    if request.user.is_anonymous():
+        return {}
+    return {
+        "notifications_check_interval":
+        int(parameters.get_admin("TOP_NOTIFICATIONS_CHECK_INTERVAL")) * 1000,
+        "top_notifications": events.raiseQueryEvent(
+            "TopNotifications", request.user, False)
+    }
diff --git a/modoboa/core/templates/core/information.html b/modoboa/core/templates/core/information.html
index f74c13139..23f6264c2 100644
--- a/modoboa/core/templates/core/information.html
+++ b/modoboa/core/templates/core/information.html
@@ -1,5 +1,13 @@
 {% load i18n core_tags lib_tags %}
 <h2>{% trans "Information" %} <small>{% trans "Various information about Modoboa" %}</small></h2><hr>
+{% if new_version %}
+<div class="alert alert-block alert-success">
+  <h4>{% trans "An update is available!" %}</h4>
+  {% blocktrans with version=new_version.version changelog_url=new_version.changelog_url %}
+  Modoboa <strong>{{ version }}</strong> is available for download. The list of all changes is available <a href="{{ changelog_url }}" target="_blank">here</a>.
+  {% endblocktrans %}
+</div>
+{% endif %}
 <div class="alert alert-info">Modoboa <strong>{% get_version %}</strong> {% trans "is currently in use." %}</div>
 
 <h3>{% trans "Active users" %}</h3>
diff --git a/modoboa/core/templatetags/core_tags.py b/modoboa/core/templatetags/core_tags.py
index e1b5ebce1..73aac4899 100644
--- a/modoboa/core/templatetags/core_tags.py
+++ b/modoboa/core/templatetags/core_tags.py
@@ -211,12 +211,6 @@ def load_optionalmenu(user):
     )
 
 
-@register.simple_tag
-def load_notifications(user):
-    content = events.raiseQueryEvent("TopNotifications", user)
-    return "".join(content)
-
-
 @register.simple_tag
 def display_messages(msgs):
     text = ""
diff --git a/modoboa/core/urls.py b/modoboa/core/urls.py
index c677f73c4..5db970d7c 100644
--- a/modoboa/core/urls.py
+++ b/modoboa/core/urls.py
@@ -1,4 +1,4 @@
-from django.conf.urls import patterns
+from django.conf.urls import patterns, url
 
 
 urlpatterns = patterns(
@@ -7,13 +7,18 @@ urlpatterns = patterns(
     (r'^accounts/login/$', 'modoboa.core.views.auth.dologin'),
     (r'^accounts/logout/$', 'modoboa.core.views.auth.dologout'),
 
-    (r'^core/$', 'modoboa.core.views.admin.viewsettings'),
+    url(r'^core/$', 'modoboa.core.views.admin.viewsettings',
+        name="admin_index"),
     (r'^core/parameters/$', 'modoboa.core.views.admin.viewparameters'),
     (r'^core/parameters/save/$', 'modoboa.core.views.admin.saveparameters'),
     (r'^core/extensions/$', 'modoboa.core.views.admin.viewextensions'),
     (r'^core/extensions/save/$', 'modoboa.core.views.admin.saveextensions'),
-    (r'^core/info/$', 'modoboa.core.views.admin.information'),
+    url(r'^core/info/$', 'modoboa.core.views.admin.information',
+        name="information"),
     (r'^core/logs/$', 'modoboa.core.views.admin.logs'),
+    url(r'^core/top_notifications/check/$',
+        'modoboa.core.views.admin.check_top_notifications',
+        name='check_top_notifications'),
 
     (r'^user/$', 'modoboa.core.views.user.index'),
     (r'^user/preferences/$', 'modoboa.core.views.user.preferences'),
diff --git a/modoboa/core/utils.py b/modoboa/core/utils.py
new file mode 100644
index 000000000..200bd41e9
--- /dev/null
+++ b/modoboa/core/utils.py
@@ -0,0 +1,32 @@
+"""
+Utility functions.
+"""
+import os
+import pkg_resources
+
+import requests
+
+from django.conf import settings
+
+from versionfield.constants import DEFAULT_NUMBER_BITS
+from versionfield.version import Version
+
+from modoboa.lib import parameters
+
+
+def new_version_available():
+    """Check if a new version of Modoboa is available."""
+    if parameters.get_admin("CHECK_NEW_VERSIONS") == "no":
+        return None
+    local_version = pkg_resources.get_distribution("modoboa").version
+    url = os.path.join(settings.MODOBOA_API_URL, "current_version/")
+    resp = requests.get(url, params={
+        "client_version": pkg_resources.get_distribution("modoboa").version
+    })
+    if resp.status_code != 200:
+        return None
+    resp = resp.json()
+    version = Version(resp["version"], DEFAULT_NUMBER_BITS)
+    if version <= Version(local_version, DEFAULT_NUMBER_BITS):
+        return None
+    return resp
diff --git a/modoboa/core/views/admin.py b/modoboa/core/views/admin.py
index 26f97e0a9..e2b12671b 100644
--- a/modoboa/core/views/admin.py
+++ b/modoboa/core/views/admin.py
@@ -4,12 +4,13 @@ from django.utils.translation import ugettext as _
 from django.contrib.auth.decorators import (
     login_required, user_passes_test
 )
-from modoboa.lib import parameters
+from modoboa.lib import events, parameters
 from modoboa.lib.webutils import (
     _render_to_string, render_to_json_response
 )
 from modoboa.lib.listing import get_sort_order, get_listing_page
 from modoboa.core.models import Extension, Log
+from modoboa.core.utils import new_version_available
 from modoboa.core.tables import ExtensionsTable
 
 
@@ -94,7 +95,9 @@ def saveextensions(request):
 @user_passes_test(lambda u: u.is_superuser)
 def information(request, tplname="core/information.html"):
     return render_to_json_response({
-        "content": render_to_string(tplname, {})
+        "content": render_to_string(tplname, {
+            "new_version": new_version_available() 
+        }),
     })
 
 
@@ -118,3 +121,12 @@ def logs(request, tplname="core/logs.html"):
         "page": page.number,
         "paginbar": pagination_bar(page),
     })
+
+@login_required
+def check_top_notifications(request):
+    """
+    AJAX service to check for new top notifications to display.
+    """
+    return render_to_json_response(
+        events.raiseQueryEvent("TopNotifications", request.user, True)
+    )
diff --git a/modoboa/extensions/amavis/app_settings.py b/modoboa/extensions/amavis/app_settings.py
index 9d933476c..9e777e281 100644
--- a/modoboa/extensions/amavis/app_settings.py
+++ b/modoboa/extensions/amavis/app_settings.py
@@ -17,7 +17,7 @@ class ParametersForm(AdminParametersForm):
     )
 
     sep1 = SeparatorField(label=_("Messages releasing"))
-                          
+
     released_msgs_cleanup = YesNoField(
         label=_("Remove released messages"),
         initial="no",
@@ -49,12 +49,6 @@ class ParametersForm(AdminParametersForm):
         initial="/var/amavis/amavisd.sock",
         help_text=_("Path to the PDP server socket (if unix mode)")
     )
-    
-    check_requests_interval = forms.IntegerField(
-        label=_("Check requests interval"),
-        initial=30,
-        help_text=_("Interval between two release requests checks")
-    )
 
     user_can_release = YesNoField(
         label=_("Allow direct release"),
diff --git a/modoboa/extensions/amavis/general_callbacks.py b/modoboa/extensions/amavis/general_callbacks.py
index 1246c7202..b86ab7cf8 100644
--- a/modoboa/extensions/amavis/general_callbacks.py
+++ b/modoboa/extensions/amavis/general_callbacks.py
@@ -53,35 +53,6 @@ def extra_static_content(caller, user):
     if user.group == "SimpleUsers":
         return []
 
-    if caller == 'top' and parameters.get_admin("USER_CAN_RELEASE") == 'no':
-        tpl = Template("""<script type="text/javascript">
-$(document).ready(function() {
-    var poller = new Poller("{{ url }}", {
-        interval: {{ interval }},
-        success_cb: function(data) {
-            var $link = $("#nbrequests");
-            var $maincounter = $("#alerts-counter");
-
-            if (data.requests > 0) {
-                $maincounter.html(data.requests);
-                $link.children("span").html(data.requests);
-                $maincounter.closest('div').removeClass('hidden');
-            } else {
-                $maincounter.closest('div').addClass('hidden');
-            }
-        }
-    });
-});
-</script>
-""")
-        return [tpl.render(
-            Context({
-                'url': reverse("modoboa.extensions.amavis.views.nbrequests"),
-                'interval': int(parameters.get_admin("CHECK_REQUESTS_INTERVAL")) * 1000,
-                'text': _("pending requests"),
-            })
-        )]
-
     if caller == 'domains':
         tpl = Template("""<script type="text/javascript">
 $(document).bind('domform_init', function() {
@@ -95,35 +66,25 @@ $(document).bind('domform_init', function() {
 
 
 @events.observe("TopNotifications")
-def display_requests(user):
+def check_for_pending_requests(user, include_all):
+    """
+    Check if release requests are pending.
+    """
     from .sql_listing import get_wrapper
 
     if parameters.get_admin("USER_CAN_RELEASE") == "yes" \
             or user.group == "SimpleUsers":
         return []
     nbrequests = get_wrapper().get_pending_requests(user)
-
+    if not nbrequests:
+        return [{"id": "nbrequests", "counter": 0}] if include_all \
+            else []
     url = reverse("modoboa.extensions.amavis.views.index")
     url += "#listing/?viewrequests=1"
-    tpl = Template("""<ul class="nav pull-right {{ css }}">
-  <li class="dropdown">
-    <a href="#" class="dropdown-toggle" data-toggle="dropdown">
-      <i class="icon-white icon-bell"></i> <span id="alerts-counter" class="label label-important">{{ nbrequests }}</span>
-    </a>
-    <ul class="dropdown-menu">
-      <li>
-        <a id="nbrequests" href="{{ url }}">
-          <span class="label label-important">{{ nbrequests }}</span> {{ label }}
-        </a>
-      </li>
-    </ul>
-  </li>
-</ul>""")
-    css = "hidden" if nbrequests == 0 else ""
-    return [tpl.render(Context(dict(
-        label=_("Pending requests"), url=url, css=css,
-        nbrequests=nbrequests
-    )))]
+    return [{
+        "id": "nbrequests", "url": url, "text": _("Pending requests"),
+        "counter": nbrequests, "level": "important"
+    }]
 
 
 def send_amavis_form():
diff --git a/modoboa/extensions/amavis/urls.py b/modoboa/extensions/amavis/urls.py
index 6c79062ee..8e4cb1326 100644
--- a/modoboa/extensions/amavis/urls.py
+++ b/modoboa/extensions/amavis/urls.py
@@ -6,7 +6,6 @@ urlpatterns = patterns(
     (r'^listing/$', '_listing'),
     (r'^getmailcontent/(?P<mail_id>[\w\-\+]+)/$', 'getmailcontent'),
     (r'^process/$', 'process'),
-    (r'^nbrequests/$', 'nbrequests'),
     (r'^delete/(?P<mail_id>[\w\-\+]+)/$', 'delete'),
     (r'^release/(?P<mail_id>[\w\-\+]+)/$', 'release'),
     (r'^(?P<mail_id>[\w\-\+]+)/$', 'viewmail'),
diff --git a/modoboa/extensions/amavis/views.py b/modoboa/extensions/amavis/views.py
index 8eb7da2fb..b375efcd3 100644
--- a/modoboa/extensions/amavis/views.py
+++ b/modoboa/extensions/amavis/views.py
@@ -288,10 +288,3 @@ def process(request):
 
     if request.POST["action"] == "delete":
         return delete(request, ids)
-
-
-@login_required
-@user_passes_test(lambda u: u.group != 'SimpleUsers')
-def nbrequests(request):
-    result = get_wrapper().get_pending_requests(request.user)
-    return render_to_json_response({'requests': result})
diff --git a/modoboa/static/js/top_notifications.js b/modoboa/static/js/top_notifications.js
new file mode 100644
index 000000000..adaaaa020
--- /dev/null
+++ b/modoboa/static/js/top_notifications.js
@@ -0,0 +1,101 @@
+/**
+ * Top notifications poller.
+ */
+
+var TopNotifications = function(options) {
+    this.initialize(options);
+};
+
+TopNotifications.prototype = {
+    constructor: TopNotifications,
+
+    defaults: {
+        container_id: "#top_notifications",
+        global_counter_id: "#alerts-counter",
+        url: null,
+        interval: 1000
+    },
+
+    /**
+     * Constructor.
+     */
+    initialize: function(options) {
+        this.options = $.extend({}, this.defaults, options);
+        this.poller = new Poller(this.options.url, {
+            interval: this.options.interval,
+            success_cb: $.proxy(this.update, this)
+        });
+        this.$container = $(this.options.container_id);
+    },
+
+    /**
+     * Build a notification entry content.
+     */
+    build_link_content: function(data) {
+        var content = "";
+
+        if (data.counter) {
+            content = "<span class='label label-" +
+                data.level + "'>" + data.counter + "</span> " +
+                data.text;
+        } else {
+            content = "<i class='icon-info-sign'></i> " + data.text;
+        }
+        return content;
+    },
+
+    /**
+     * Append an entry to the notification list.
+     */
+    append_entry: function(data) {
+        if ((data.counter !== undefined && data.counter === 0) ||
+            (data.counter === undefined && data.text === undefined)) {
+            return;
+        }
+
+        var $li = $("<li />");
+
+        $li.append(
+            $("<a />", {
+                id: data.id, href: data.url,
+                html: this.build_link_content(data)
+            })
+        );
+        this.$container.find(".dropdown-menu").append($li);
+    },
+
+    /**
+     * Update an existing entry in the notification list.
+     */
+    update_entry: function(data) {
+        var $link = $("#" + data.id);
+
+        if ((data.counter !== undefined && data.counter === 0) ||
+            (data.counter === undefined && data.text === undefined)) {
+            $link.parent().remove();
+            return;
+        }
+        $link.html(this.build_link_content(data));
+    },
+
+    /**
+     * Poller callback.
+     */
+    update: function(data) {
+        for (var cpt = 0; cpt < data.length; cpt++) {
+            var $link = $("#" + data[cpt].id);
+            if (!$link.length) {
+                this.append_entry(data[cpt]);
+            } else {
+                this.update_entry(data[cpt]);
+            }
+        }
+        var $entries = this.$container.find(".dropdown-menu li");
+        if ($entries.length) {
+            this.$container.removeClass("hidden");
+            $(this.options.global_counter_id).html($entries.length);
+        } else {
+            this.$container.addClass("hidden");
+        }
+    }
+};
diff --git a/modoboa/templates/common/top_notifications.html b/modoboa/templates/common/top_notifications.html
new file mode 100644
index 000000000..d11b52934
--- /dev/null
+++ b/modoboa/templates/common/top_notifications.html
@@ -0,0 +1,20 @@
+<ul id="top_notifications" class="nav pull-right{% if not top_notifications %} hidden{% endif %}">
+  <li class="dropdown">
+    <a href="#" class="dropdown-toggle" data-toggle="dropdown">
+      <i class="icon-white icon-bell"></i> <span id="alerts-counter" class="label label-important">{{ top_notifications|length }}</span>
+    </a>
+    <ul class="dropdown-menu">
+      {% for notification in top_notifications %}
+      <li>
+        <a id="{{ notification.id }}" href="{{ notification.url }}">
+          {% if notification.counter %}
+          <span class="label label-{{ notification.level }}">{{ notification.counter }}</span> {{ notification.text|safe }}
+          {% else %}
+          <i class="icon-info-sign"></i> {{ notification.text|safe }}
+          {% endif %}
+        </a>
+      </li>
+      {% endfor %}
+    </ul>
+  </li>
+</ul>
diff --git a/modoboa/templates/nlayout.html b/modoboa/templates/nlayout.html
index bd6d9275e..0cff6e3cc 100644
--- a/modoboa/templates/nlayout.html
+++ b/modoboa/templates/nlayout.html
@@ -18,10 +18,19 @@
     <script src="{{ STATIC_URL }}js/confirmation.js" type="text/javascript"></script>
     <script src="{{ STATIC_URL }}js/notify.js" type="text/javascript"></script>
     <script src="{{ STATIC_URL }}js/poller.js" type="text/javascript"></script>
+    <script src="{{ STATIC_URL }}js/top_notifications.js" type="text/javascript"></script>
     {% url "django.views.i18n.javascript_catalog" as catalog_url %}
     <script type="text/javascript" src="{{ catalog_url }}"></script>
     <script type="text/javascript">
+      var top_notifications;
+
       set_static_url("{{ STATIC_URL }}");
+      $(document).ready(function() {
+          top_notifications = new TopNotifications({
+              url: "{% url 'check_top_notifications' %}",
+              interval: {{ notifications_check_interval }}
+          });
+      });
     </script>
     {% extra_static_content "top" user %}
     {% block html_head %}{% endblock %}
@@ -46,7 +55,7 @@
           <ul class="nav pull-right">
             {% if selection %}{% user_menu user selection %}{% else %}{% user_menu user "" %}{% endif %}
           </ul>
-          <div class="pull-right">{% load_notifications user %}</div>
+          <div class="pull-right">{% include "common/top_notifications.html" %}</div>
         </div>
       </div>
     </div>    
diff --git a/requirements.txt b/requirements.txt
index 9c7b48790..01c6c8f36 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,3 +10,4 @@ argparse
 rfc6266
 factory-boy
 passlib
+-e git+https://github.com/tonioo/django-versionfield.git#egg=django-versionfield