diff --git a/app/controllers/conferences_controller.rb b/app/controllers/conferences_controller.rb
index bbd075095..1bed4880d 100644
--- a/app/controllers/conferences_controller.rb
+++ b/app/controllers/conferences_controller.rb
@@ -135,7 +135,9 @@ def create
   def update
     authorize @conference, :orga?
     respond_to do |format|
-      if @conference.update_attributes(existing_conference_params)
+      if not params[:conference]
+        format.html { redirect_to(edit_conference_path(conference_acronym: @conference.acronym), notice: t('conferences_module.notice_conference_not_updated')) }
+      elsif @conference.update_attributes(existing_conference_params)
         format.html { redirect_to(edit_conference_path(conference_acronym: @conference.acronym), notice: t('conferences_module.notice_conference_updated')) }
       else
         flash_model_errors(@conference)
diff --git a/app/views/conferences/_form.html.haml b/app/views/conferences/_form.html.haml
index 6f9928700..feccebcc0 100644
--- a/app/views/conferences/_form.html.haml
+++ b/app/views/conferences/_form.html.haml
@@ -53,7 +53,11 @@
 :coffeescript
   duration_to_time = (minutes) ->
     two_digits = (n) ->
-      (n).toString().padStart(2, '0')
+      if n < 10
+        return "0" + n
+      else
+        return "" + n
+
     two_digits(minutes // 60) + ':' + two_digits(minutes % 60)
     
   render_duration_checkboxes = () ->
@@ -65,7 +69,7 @@
     ul.empty()
     for slots in [1..max_timeslots]
       minutes = slots * minutes_per_slot
-      is_checked = checked_items.includes(minutes.toString()) || minutes == default_submission_in_minutes 
+      is_checked = minutes.toString() in checked_items || minutes == default_submission_in_minutes
       is_disabled = minutes==default_submission_in_minutes
       item = $('<input />', { class: 'accepted-duration-checkbox', type: 'checkbox', value: minutes, checked: is_checked, disabled: is_disabled})
       ul.append(item).append(duration_to_time(minutes)).append('<br/>')
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 329f9d95c..45465cb75 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -536,6 +536,7 @@ de:
       Fügen Sie mit der Schaltfläche rechts eine Konferenz hinzu.
     notice_bulk_notification_queued: Alle Benachrichtigungen für die Einreichungen in %{notification} an den Ticket-Server übergeben.
     notice_conference_created: Die Konferenz wurde erfolgreich erstellt.
+    notice_conference_not_updated: Konferenz wurde nicht aktualisiert.
     notice_conference_updated: Die Konferenz wurde erfolgreich aktualisiert.
     past_conferences: Frühere Konferenzen
     recent_changes: Letzte Änderungen
diff --git a/config/locales/en.yml b/config/locales/en.yml
index b4f38bd39..21cffed0e 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -515,6 +515,7 @@ en:
       button on the right.
     notice_bulk_notification_queued: Bulk notifications for events in %{notification} enqueued.
     notice_conference_created: Conference was successfully created.
+    notice_conference_not_updated: Conference was not updated.
     notice_conference_updated: Conference was successfully updated.
     past_conferences: Past Conferences
     recent_changes: Recent changes
diff --git a/config/locales/es.yml b/config/locales/es.yml
index 2c286fc37..572f8a64d 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -560,6 +560,7 @@ es:
       botón a la derecha.
     notice_bulk_notification_queued: Notificaciones masivas para eventos en %{notification} en cola.
     notice_conference_created: La conferencia fue creada con éxito.
+    notice_conference_not_updated: La conferencia no se actualizó.
     notice_conference_updated: La conferencia fue actualizada con éxito.
     past_conferences: Conferencias pasadas
     recent_changes: Cambios recientes
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index f87781fc3..fd3dc4006 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -524,6 +524,7 @@ fr:
       en cliquant sur le bouton de droite.
     notice_bulk_notification_queued: Groupe de notifications pour les évènements dans %{notification} mises en file d’attente..
     notice_conference_created: Conférence créée avec succès.
+    notice_conference_not_updated: La conférence n'a pas été mise à jour.
     notice_conference_updated: Conférence mise à jour avec succès.
     past_conferences: Conférences passées
     recent_changes: Changements récents
diff --git a/config/locales/it.yml b/config/locales/it.yml
index 5047a84a2..fa6cbb43d 100644
--- a/config/locales/it.yml
+++ b/config/locales/it.yml
@@ -524,6 +524,7 @@ it:
       cliccando sul tasto destro.
     notice_bulk_notification_queued: Gruppo di notifica per eventi in %{notification} in coda.
     notice_conference_created: Conferenza creata con successo.
+    notice_conference_not_updated: La conferenza non è stata aggiornata.
     notice_conference_updated: Conferenza aggiornata con successo.
     past_conferences: Conferenze passate
     recent_changes: Cambiamenti recenti
diff --git a/config/locales/pt-BR.yml b/config/locales/pt-BR.yml
index 14ab36927..cf0f5a6f1 100644
--- a/config/locales/pt-BR.yml
+++ b/config/locales/pt-BR.yml
@@ -537,6 +537,7 @@ pt-BR:
       botão à direita.
     notice_bulk_notification_queued: Notificações em massa para eventos em %{notification} enfileirados.
     notice_conference_created: Conferência foi criada com sucesso.
+    notice_conference_not_updated: A conferência não foi atualizada.
     notice_conference_updated: Conferência foi atualizada com sucesso.
     past_conferences: Conferências passadas
     recent_changes: Mudanças recentes
diff --git a/config/locales/ru.yml b/config/locales/ru.yml
index a7fe2c135..bd8333903 100644
--- a/config/locales/ru.yml
+++ b/config/locales/ru.yml
@@ -515,6 +515,7 @@ ru:
       справа.
     notice_bulk_notification_queued: Массовые уведомления для событий в %{notification} в очереди.
     notice_conference_created: Конференция была успешно создана.
+    notice_conference_not_updated: Конференция не обновлялась.
     notice_conference_updated: Конференция была успешно обновлена.
     past_conferences: Прошедшие конференции
     recent_changes: Недавние изменения
diff --git a/config/locales/zh.yml b/config/locales/zh.yml
index e02759bb1..eeef5a61c 100644
--- a/config/locales/zh.yml
+++ b/config/locales/zh.yml
@@ -515,6 +515,7 @@ zh:
       按钮在右边。
     notice_bulk_notification_queued: 批量通知%{notification}中的事件入队。
     notice_conference_created: 会议成功创建。
+    notice_conference_not_updated: 会议未更新。
     notice_conference_updated: 会议已成功更新。
     past_conferences: 过去的会议
     recent_changes: 近期变动
diff --git a/test/features/editing_conference_test.rb b/test/features/editing_conference_test.rb
index 877729c44..c352067a0 100644
--- a/test/features/editing_conference_test.rb
+++ b/test/features/editing_conference_test.rb
@@ -26,4 +26,17 @@ class EditingConferenceTest < FeatureTest
     assert_content page, 'Events'
     assert_content page, Event.last.title
   end
+
+  it 'edit classifiers', js: true do
+    sign_in_user(@admin)
+    visit "/#{@conference.acronym}/conference/edit_classifiers"
+    assert_content page, 'Here you can create and edit the classifiers'
+    click_on 'Update conference'
+    assert_content page, 'Conference was not updated.'
+    click_on 'Classifiers'
+    click_on 'Add classifier'
+    fill_in 'Name', with: 'classifier1'
+    click_on 'Update conference'
+    assert_content page, 'Conference was successfully updated.'
+  end
 end