diff --git a/rhodecode/apps/repository/utils.py b/rhodecode/apps/repository/utils.py
--- a/rhodecode/apps/repository/utils.py
+++ b/rhodecode/apps/repository/utils.py
@@ -107,5 +107,5 @@ def validate_default_reviewers(review_me
     return reviewers
 
 
-def validate_observers(observer_members):
+def validate_observers(observer_members, reviewer_rules):
     return {}
diff --git a/rhodecode/config/middleware.py b/rhodecode/config/middleware.py
--- a/rhodecode/config/middleware.py
+++ b/rhodecode/config/middleware.py
@@ -412,6 +412,7 @@ def sanitize_settings_and_apply_defaults
     """
 
     settings.setdefault('rhodecode.edition', 'Community Edition')
+    settings.setdefault('rhodecode.edition_id', 'CE')
 
     if 'mako.default_filters' not in settings:
         # set custom default filters if we don't have it defined
diff --git a/rhodecode/lib/base.py b/rhodecode/lib/base.py
--- a/rhodecode/lib/base.py
+++ b/rhodecode/lib/base.py
@@ -293,6 +293,7 @@ def attach_context_attributes(context, r
     context.rc_config = rc_config
     context.rhodecode_version = rhodecode.__version__
     context.rhodecode_edition = config.get('rhodecode.edition')
+    context.rhodecode_edition_id = config.get('rhodecode.edition_id')
     # unique secret + version does not leak the version but keep consistency
     context.rhodecode_version_hash = calculate_version_hash(config)
 
diff --git a/rhodecode/public/css/main.less b/rhodecode/public/css/main.less
--- a/rhodecode/public/css/main.less
+++ b/rhodecode/public/css/main.less
@@ -495,7 +495,8 @@ ul.auth_plugins {
     padding-top: 10px;
 }
 
-#add_reviewer_input {
+#add_reviewer_input,
+#add_observer_input {
     padding-top: 10px
 }
 
diff --git a/rhodecode/templates/pullrequests/pullrequest.mako b/rhodecode/templates/pullrequests/pullrequest.mako
--- a/rhodecode/templates/pullrequests/pullrequest.mako
+++ b/rhodecode/templates/pullrequests/pullrequest.mako
@@ -177,7 +177,7 @@
                                         <span class="calculate-reviewers">
                                             <h4>${_('loading...')}</h4>
                                         </span>
-
+                                        % if c.rhodecode_edition_id == 'EE':
                                         <div id="observers" class="pr-details-content observers">
                                             ## members goes here, filled via JS based on initial selection !
                                             <input type="hidden" name="__start__" value="observer_members:sequence">
@@ -193,7 +193,12 @@
                                                 </div>
                                             </div>
                                         </div>
-
+                                        % else:
+                                            <h4>${_('This feature is available in RhodeCode EE edition only. Contact {sales_email} to obtain a trial license.').format(sales_email='<a href="mailto:sales@rhodecode.com">sales@rhodecode.com</a>')|n}</h4>
+                                            <p>
+                                                Pull request observers allows adding users who don't need to leave mandatory votes, but need to be aware about certain changes.
+                                            </p>
+                                        % endif
                                     </div>
 
                                 </div>
diff --git a/rhodecode/templates/pullrequests/pullrequest_show.mako b/rhodecode/templates/pullrequests/pullrequest_show.mako
--- a/rhodecode/templates/pullrequests/pullrequest_show.mako
+++ b/rhodecode/templates/pullrequests/pullrequest_show.mako
@@ -624,6 +624,7 @@
             </div>
 
             ## OBSERVERS
+            % if c.rhodecode_edition_id == 'EE':
             <div class="sidebar-element clear-both">
                 <% vote_title = _ungettext(
                         '{} observer without voting right.',
@@ -674,6 +675,7 @@
                     %endif
                 </div>
             </div>
+            % endif
 
             ## TODOs
             <div class="sidebar-element clear-both">