diff --git a/.env.sample b/.env.sample
index 6a8e41d24..d63ef287a 100644
--- a/.env.sample
+++ b/.env.sample
@@ -10,6 +10,8 @@ API_KEY=
 
 UI_THEME=ontoportal
 
+TWITTER_NEWS=
+
 BIOMIXER_URL=
 BIOMIXER_APIKEY=
 
diff --git a/app/controllers/admin/categories_controller.rb b/app/controllers/admin/categories_controller.rb
index 1e3ba2ed8..f704248c6 100644
--- a/app/controllers/admin/categories_controller.rb
+++ b/app/controllers/admin/categories_controller.rb
@@ -11,6 +11,15 @@ class Admin::CategoriesController < ApplicationController
 
   def index
     @categories = _categories
+
+    @parents_list = Hash.new { |hash, key| hash[key] = [] }
+    @categories.each do |category|
+      category.parentCategory.each do |parent|
+        @parents_list[parent] << category.acronym
+      end
+    end
+
+
   end
 
   def new
diff --git a/app/controllers/ontologies_controller.rb b/app/controllers/ontologies_controller.rb
index 597a238e3..291549cee 100644
--- a/app/controllers/ontologies_controller.rb
+++ b/app/controllers/ontologies_controller.rb
@@ -60,18 +60,20 @@ def ontologies_filter
         end
       end.flatten
 
-      unless request_portals.length == 1
+      if federated_request?
         streams += [
           replace('categories_refresh_for_federation') do
-            key = "categories"
+            key = 'categories'
             objects, checked_values, _ = @filters[key.to_sym]
             objects = keep_only_root_categories(objects)
+
             helpers.browse_filter_section_body(checked_values: checked_values,
                                                key: key, objects: objects,
                                                counts: @count_objects[key.to_sym])
           end
         ]
       end
+
     else
       streams = [replace("ontologies_list_view-page-#{@page.page}", partial: 'ontologies/browser/ontologies')]
     end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index aeb77f43c..0ee8514e0 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -454,5 +454,13 @@ def categories_select(id: nil, name: nil, selected: 'None')
     render Input::SelectComponent.new(id: id, name: name, value: categories_for_select, selected: selected, multiple: true)
   end
 
+  def category_is_parent?(parents_list, category)
+    is_parent = parents_list.keys.include?(category.id)
+    parent_error_message = t('admin.categories.category_used_parent')
+    parents_list[category.id].each do |c|
+      parent_error_message = "#{parent_error_message} #{c}"
+    end
+    [is_parent,parent_error_message]
+  end
 
 end
diff --git a/app/views/admin/categories/_category.html.haml b/app/views/admin/categories/_category.html.haml
index 649149ed1..0e812309f 100644
--- a/app/views/admin/categories/_category.html.haml
+++ b/app/views/admin/categories/_category.html.haml
@@ -1,5 +1,6 @@
 %tr.human{:id => category.id.split('/').last}
-  - count = category.ontologies&.size || 0
+  - count = category.ontologies&.size || 0 
+  - is_parent, parent_error_message = category_is_parent?(@parents_list, category)
   %td
     %div{style: 'width: 250px'}
       %div.text-truncate{title: category.name}
@@ -18,8 +19,11 @@
         = link_to_modal(nil, edit_admin_category_path(category.id.split('/').last), data: {show_modal_title_value:  category.name}) do
           = t('admin.categories.edit_button')
       %span
-        - if count.zero?
-          = button_to t('admin.categories.delete'), CGI.unescape(admin_category_path(category.id.split('/').last)), method: :delete, class: 'btn btn-link',  form: {data: { turbo: true, turbo_confirm: t('admin.categories.turbo_confirm'), turbo_frame: '_top'}}
-        - else
+        - if !count.zero?
           %span{data: { controller: 'tooltip' }, title: t('admin.categories.info_error_delete')}
             = link_to t('admin.categories.delete'), "", class: 'btn btn-link disabled'
+        - elsif is_parent
+          %span{data: { controller: 'tooltip' }, title: parent_error_message}
+            = link_to t('admin.categories.delete'), "", class: 'btn btn-link disabled'
+        - else
+          = button_to t('admin.categories.delete'), CGI.unescape(admin_category_path(category.id.split('/').last)), method: :delete, class: 'btn btn-link',  form: {data: { turbo: true, turbo_confirm: t('admin.categories.turbo_confirm'), turbo_frame: '_top'}}
diff --git a/app/views/home/index.html.haml b/app/views/home/index.html.haml
index 6cc474bbc..24e2bfd08 100644
--- a/app/views/home/index.html.haml
+++ b/app/views/home/index.html.haml
@@ -237,4 +237,4 @@
   }
   function submitRecommender(){
   document.getElementById("recommender_submit").click()
-  }
\ No newline at end of file
+  }
diff --git a/app/views/visits/index.html.haml b/app/views/visits/index.html.haml
index 45085f09e..1c3925284 100644
--- a/app/views/visits/index.html.haml
+++ b/app/views/visits/index.html.haml
@@ -13,7 +13,7 @@
       %tbody
         - count = 0
         - @analytics.onts.each do |visits|
-          - ont = @ontologies_hash[visits[:ont].to_s]
+          - ont = @ontologies_hash[visits[:ont].to_s.split('/').last]
           - next if ont.nil?
           - count += 1
           %tr
diff --git a/config/bioportal_config_env.rb.sample b/config/bioportal_config_env.rb.sample
index 845adce93..13cb23b6e 100644
--- a/config/bioportal_config_env.rb.sample
+++ b/config/bioportal_config_env.rb.sample
@@ -8,6 +8,9 @@ $ORG_URL = ENV['ORG_URL']
 # Site name (required)
 $SITE = ENV['SITE']
 
+# Twitter section
+$TWITTER_NEWS = ENV["TWITTER_NEWS"]
+
 # Full string for site, EX: "NCBO BioPortal", do not modify
 $ORG_SITE = $ORG.nil? || $ORG.empty? ? $SITE : "#{$ORG} #{$SITE}"
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index d3b7e4884..c90bc7286 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -194,6 +194,7 @@ en:
       problem_of_updating: Problem updating the category - %{message}
       category_deleted_successfully: Category successfully deleted in %{time}s
       problem_of_deleting: Problem deleting the category - %{message}
+      category_used_parent: "Can't delete category, used as a parent category for:"
       edit_button: "Edit"
       delete: Delete
       info_error_delete: Can't delete this category because still used
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 5ce6e7f89..abd34fbb6 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -200,6 +200,7 @@ fr:
       problem_of_updating: Problème lors de la mise à jour de la catégorie - %{message}
       category_deleted_successfully: Catégorie supprimée avec succès en %{time}s
       problem_of_deleting: Problème lors de la suppression de la catégorie - %{message}
+      category_used_parent: "Impossible de supprimer la catégorie, utilisée comme catégorie parente pour:"
       edit_button: Éditer
       delete: Supprimer
       info_error_delete: Impossible de supprimer cette catégorie car elle est encore utilisée