diff --git a/Dockerfile b/Dockerfile
index 83929fe22..dccbd90ee 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 ARG RUBY_PATH=/usr/local/
 ARG RUBY_VERSION=2.7.2
 
-FROM ubuntu:16.04 AS rubybuild
+FROM ubuntu:20.04 AS rubybuild
 ARG RUBY_PATH
 ARG RUBY_VERSION
 
diff --git a/Gemfile b/Gemfile
index 7c2898a62..f32898483 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,7 @@
 source "http://rubygems.org"
 
 ruby "2.7.2"
+# ruby "2.7.8"
 
 #gem "rails", "~> 3.2.16"
 gem "rails", "5.1.7"
@@ -106,6 +107,8 @@ gem "newrelic_rpm"
 gem "dotenv-rails"
 gem "tzinfo-data"
 
+gem "ancestry" # Para otimização de queries de posts do fórum
+
 group :development do
   gem "foreman", require: false
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 997e653c1..1596d09a3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -51,6 +51,8 @@ GEM
     akami (1.2.2)
       gyoku (>= 0.4.0)
       nokogiri
+    ancestry (3.2.1)
+      activerecord (>= 4.2.0)
     arel (8.0.0)
     ast (2.4.2)
     attr_required (1.0.1)
@@ -526,6 +528,7 @@ PLATFORMS
 DEPENDENCIES
   actionpack-action_caching (~> 1.2.0)
   actionpack-page_caching (~> 1.2.3)
+  ancestry
   awesome_print
   better_errors (~> 2.4.0)
   bigbluebutton-api-ruby (~> 1.6.0)
diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index 8b0ec860a..5a6894ebd 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -7,6 +7,7 @@ class PostsController < ApplicationController
   before_action :prepare_for_pagination
   before_action :set_current_user, only: [:destroy, :create, :update, :publish, :post_files]
 
+  #autoriza é o metodo para autorizar todas as çãoes em um controlador de recursos
   load_and_authorize_resource except: [:index, :user_posts, :create, :show, :evaluate, :publish, :post_files]
 
   ## GET /discussions/1/posts
@@ -41,16 +42,23 @@ def index
       if (p['display_mode'] == "list" || params[:format] == "json")
         # se for em forma de lista ou para o mobilis, pesquisa pelo método posts
         p['page'] ||= @current_page
-        p['type'] ||= "history"
         p['date'] = DateTime.parse(p['date']) if params[:format] == "json" && p.include?('date')
         @posts    = @discussion.posts_not_limit(p, @allocation_tags, current_user.id).paginate(page: params[:page] || 1, per_page: Rails.application.config.items_per_page)
-      elsif (@display_mode == 'user' )
-        my_list = true
-        @posts = @discussion.posts_by_allocation_tags_ids(@allocation_tags, current_user.id, my_list).paginate(page: params[:page] || 1, per_page: Rails.application.config.items_per_page) # caso contrário, recupera e reordena os posts do nível 1 a partir das datas de seus descendentes
-      else
-        @posts = @discussion.posts_by_allocation_tags_ids(@allocation_tags, current_user.id).paginate(page: params[:page] || 1, per_page: Rails.application.config.items_per_page) # caso contrário, recupera e reordena os posts do nível 1 a partir das datas de seus descendentes
-      end
-
+                elsif (@display_mode == 'user' )
+                  my_list = true
+                  @posts = @discussion.posts_by_allocation_tags_ids(@allocation_tags, current_user.id, my_list).paginate(page: params[:page] || 1, per_page: Rails.application.config.items_per_page)
+                else
+                  @posts = @discussion.posts_for_tree_view(@allocation_tags, current_user.id, params[:page] || 1)
+
+                  # Eager loading dos filhos apenas dos posts da página atual
+                  # Evita N+1 queries ao renderizar post.children na view recursivamente
+                  # Escalável: carrega apenas filhos dos 10 posts raízes da página, não de todos os posts do banco
+                  if @posts.any?
+                    Post.includes(:files, :user, :profile)
+                        .where(ancestry: @posts.map(&:id))
+                        .load
+                  end
+                end
       if current_user.is_student?([@allocation_tags].flatten)
         @acu = AcademicAllocationUser.find_or_create_one(@academic_allocation.id, [@allocation_tags].flatten, current_user.id, nil, false, AcademicAllocationUser::STATUS[:empty])
       end
@@ -107,7 +115,7 @@ def create
     authorize! :create, Post
 
     if new_post_under_discussion(Discussion.find(params[:discussion_id]))
-      render json: {result: 1, post_id: @post.id, parent_id: @post.parent_id}, status: :created
+      render json: {result: 1, post_id: @post.id, ancestry: @post.ancestry}, status: :created
     else
       render json: { result: 0, alert: @post.errors.full_messages.join('; ') }, status: :unprocessable_entity
     end
@@ -123,7 +131,7 @@ def create
   def update
     @post = Post.find(params[:id])
     if @post.update_attributes post_params
-      render json: {success: true, post_id: @post.id, parent_id: @post.parent_id}
+      render json: {success: true, post_id: @post.id, ancestry: @post.ancestry}
     else
       render json: { result: 0, alert: @post.errors.full_messages.join('; ') }, status: :unprocessable_entity
     end
@@ -138,7 +146,7 @@ def update
   def publish
     @post = Post.find(params[:id])
     @post.update_attributes draft: false
-    render json: { success: true, post_id: @post.id, discussion_id: @post.discussion.id, content: @post.content, ac_id: @post.academic_allocation_id, parent_id: @post.parent_id }, status: :ok
+    render json: { success: true, post_id: @post.id, discussion_id: @post.discussion.id, content: @post.content, ac_id: @post.academic_allocation_id, ancestry: @post.ancestry }, status: :ok
   rescue => error
     render_json_error(error, 'discussions.error')
   end
@@ -181,10 +189,34 @@ def post_files
     render json: { alert: post.errors.full_messages.join('; ') }, status: :unprocessable_entity
   end
 
+  # TODO: Lazy loading não implementado na view
+  # Para implementar: adicionar botões .view-children-btn na view e descomentar esta action
+  # def children
+  #   @post = Post.find(params[:id])
+  #   @discussion = @post.discussion
+  #
+  #   # Re-creating instance variables needed by the partial
+  #   authorize! :index, Discussion, { on: [@allocation_tags = active_tab[:url][:allocation_tag_id] || @discussion.allocation_tags.map(&:id)], read: true }
+  #   @academic_allocation = AcademicAllocation.where(academic_tool_id: @discussion.id, academic_tool_type: 'Discussion', allocation_tag_id: [active_tab[:url][:allocation_tag_id], AllocationTag.find_by_offer_id(active_tab[:url][:id])&.id]).first
+  #   @researcher = current_user.is_researcher?(AllocationTag.where(id: @allocation_tags).map(&:related).flatten.uniq)
+  #   @class_participants = AllocationTag.get_participants(active_tab[:url][:allocation_tag_id], { all: true }).map(&:id)
+  #   @can_interact = @discussion.user_can_interact?(current_user.id)
+  #   @can_post = (can? :create, Post, on: [@allocation_tags])
+  #   @can_evaluate = can? :evaluate, Discussion, {on: [@allocation_tags]}
+  #
+  #   render partial: 'post', collection: @post.children, layout: false, locals: {
+  #     display_mode: 'tree',
+  #     can_interact: @can_interact,
+  #     can_post: @can_post,
+  #     current_user: current_user,
+  #     new_post: false
+  #   }
+  # end
+
   private
 
     def post_params
-      params.require(:post).permit(:content, :parent_id, :discussion_id, :draft, files_attributes: [:id, :attachment, :_destroy])
+      params.require(:post).permit(:content, :ancestry, :discussion_id, :draft, files_attributes: [:id, :attachment, :_destroy])
     end
 
     def new_post_under_discussion(discussion)
diff --git a/app/helpers/menu_helper.rb b/app/helpers/menu_helper.rb
index fc32645d7..56663c83d 100644
--- a/app/helpers/menu_helper.rb
+++ b/app/helpers/menu_helper.rb
@@ -26,8 +26,15 @@ def menu_list
     menus.each_with_index do |menu, idx|
       contexts = menu.contexts.pluck(:id)
       code_to_shortcut = menu.name
-      menu_item_link = link_to(t(menu.name), url_for({controller: "/#{menu.resource.controller}", action: menu.resource.action,
-        bread: menu.name, contexts: contexts.join(',')}), onclick: 'focusTitle();', onkeypress: 'focusTitle();', onkeydown: 'click_on_keypress(event, this);', class: menu.parent.nil? ? 'mysolar_menu_title' : '', :'data-shortcut' => (I18n.translate!(code_to_shortcut, scope: "shortcut.vertical_menu.code", raise: true) rescue ''), :'data-shortcut-shift' => true, :'data-shortcut-complement' => (I18n.translate!(code_to_shortcut, scope: "shortcut.vertical_menu.complement", raise: true) rescue ''))
+
+      # Ignora menus com rotas inexistentes (ex: FAQs em outra branch)
+      begin
+        menu_item_link = link_to(t(menu.name), url_for({controller: "/#{menu.resource.controller}", action: menu.resource.action,
+          bread: menu.name, contexts: contexts.join(',')}), onclick: 'focusTitle();', onkeypress: 'focusTitle();', onkeydown: 'click_on_keypress(event, this);', class: menu.parent.nil? ? 'mysolar_menu_title' : '', :'data-shortcut' => (I18n.translate!(code_to_shortcut, scope: "shortcut.vertical_menu.code", raise: true) rescue ''), :'data-shortcut-shift' => true, :'data-shortcut-complement' => (I18n.translate!(code_to_shortcut, scope: "shortcut.vertical_menu.complement", raise: true) rescue ''))
+      rescue ActionController::UrlGenerationError
+        next # Pula menus com rotas inexistentes
+      end
+
       menu_item = {contexts: contexts, bread: menu.name, link: menu_item_link}
 
       if menu.parent.nil?
diff --git a/app/models/discussion.rb b/app/models/discussion.rb
index 1db9f066e..2aed26d37 100644
--- a/app/models/discussion.rb
+++ b/app/models/discussion.rb
@@ -139,6 +139,19 @@ def posts_by_allocation_tags_ids(allocation_tags_ids = nil, user_id = nil, my_li
     (opt[:grandparent] ? posts_list.map(&:grandparent).uniq.compact : posts_list.to_a.compact.uniq)
   end
 
+  def posts_for_tree_view(allocation_tags_ids = nil, user_id = nil, page = 1)
+    allocation_tags_ids = AllocationTag.where(id: allocation_tags_ids).map(&:related).flatten.compact.uniq
+
+    discussion_posts
+      .roots
+      .includes(:files, :user, :profile)
+      .joins(academic_allocation: :allocation_tag)
+      .where(allocation_tags: { id: allocation_tags_ids })
+      .where("(draft = ? ) OR (draft = ? AND user_id = ?)", false, true, user_id)
+      .order_by_ancestry
+      .paginate(page: page, per_page: Rails.application.config.items_per_page)
+  end
+
   def posts_by_allocation_tags_ids_to_api(allocation_tags_ids = nil, user_id = nil, my_list=nil, opt = { grandparent: true, query: '', order: 'updated_at desc', limit: nil, offset: nil, select: 'DISTINCT discussion_posts.id, discussion_posts.*' })
     allocation_tags_ids = AllocationTag.where(id: allocation_tags_ids).map(&:related).flatten.compact.uniq
     posts_list = discussion_posts.includes(:files).where(opt[:query]).order(opt[:order]).limit(opt[:limit]).offset(opt[:offset]).select(opt[:select])
@@ -149,7 +162,6 @@ def posts_by_allocation_tags_ids_to_api(allocation_tags_ids = nil, user_id = nil
 
     (opt[:grandparent] ? posts_list.map(&:grandparent).uniq.compact : posts_list.compact.uniq)
   end
-
   def resume(allocation_tags_ids = nil)
     {
       id: id,
diff --git a/app/models/post.rb b/app/models/post.rb
index 626c41150..8e7a64377 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -2,19 +2,26 @@ class Post < ActiveRecord::Base
   include SentActivity
 
   self.table_name = 'discussion_posts'
+  # Adiciona a gem ancestry para gerenciar a hierarquia de forma otimizada,
+  # substituindo a recursão manual que causava lentidão.
+  # A opção `orphan_strategy: :destroy` apaga os posts filhos quando um pai é deletado,
+  # substituindo a necessidade do método `delete_with_dependents`.
+  has_ancestry orphan_strategy: :destroy
 
   belongs_to :profile
-  belongs_to :parent, class_name: 'Post'
+  # belongs_to :parent, class_name: 'Post'
   belongs_to :user
 
   belongs_to :academic_allocation, -> { where academic_tool_type: 'Discussion' }
   belongs_to :academic_allocation_user
 
-  validates :parent, presence: true, unless: -> {parent_id.blank?}
+  validates :parent, presence: true, unless: -> {ancestry.blank?}
   before_destroy :verify_children_with_raise, :can_change?, if: -> {merge.nil?}
   validate :verify_children, on: :update
-
-  has_many :children, class_name: 'Post', foreign_key: 'parent_id', dependent: :destroy
+  
+  # A associação `has_many :children` manual foi removida pois a gem `ancestry`
+  # já cria essa associação de forma otimizada, evitando conflitos.
+  # has_many :children, class_name: 'Post', foreign_key: 'ancestry', dependent: :destroy
   has_many :files, class_name: 'PostFile', foreign_key: 'discussion_post_id', dependent: :destroy
 
   accepts_nested_attributes_for :files, allow_destroy: true, reject_if: proc {|attributes| !attributes.include?(:attachment) || attributes[:attachment] == '0' || attributes[:attachment].blank?}
@@ -22,19 +29,21 @@ class Post < ActiveRecord::Base
   before_create :set_level, :verify_level
   before_destroy :remove_all_files
 
-  after_create :increment_counter
+  # Mantém last_activity_at atualizado em toda a árvore quando há atividade
+  after_create :increment_counter, :update_last_activity
   after_destroy :decrement_counter, :remove_drafts_children, :decrement_counter_draft
-  after_save :change_counter_draft, if: -> {!parent_id.nil? && saved_change_to_draft?}
-  after_save :send_email, unless: -> {parent_id.blank? || draft || parent.user_id == user_id || !merge.nil?}
+  after_save :change_counter_draft, if: -> {!ancestry.nil? && saved_change_to_draft?}
+  after_save :send_email, unless: -> {ancestry.blank? || draft || parent.user_id == user_id || !merge.nil?}
+  after_save :update_last_activity, if: -> {saved_change_to_content? || saved_change_to_updated_at?}
 
   validates :content, :profile_id, presence: true
 
   validate :can_change?, if: -> {merge.nil?}
-  validate :parent_post, if: -> {merge.nil? && !parent_id.blank?}
+  validate :parent_post, if: -> {merge.nil? && !ancestry.blank?}
 
   validate :can_set_draft?, if: -> {!new_record? && saved_change_to_draft? && draft}
 
-  before_save :set_parent, if: -> {!new_record? && saved_change_to_parent_id?}
+  before_save :set_parent, if: -> {!new_record? && saved_change_to_ancestry?}
   before_save :set_draft, if: -> {draft.nil?}
   before_save :remove_draft_children, if: -> {saved_change_to_draft? && draft}
 
@@ -48,9 +57,9 @@ def parent_post
     errors.add(:base, I18n.t('posts.error.draft')) if parent.draft
   end
 
-  # cant change parent_id
+  # cant change ancestry
   def set_parent
-    self.parent_id = parent_id_was
+    self.ancestry = ancestry_was
     return true
   end
 
@@ -87,6 +96,8 @@ def verify_children_with_raise
   end
 
   def can_change?
+    # Permite atualização apenas do updated_at (ex: touch)
+    return true if changed == ["updated_at"]
     unless (user_id == User.current.try(:id) || (User.current.try(:id) == parent.try(:user_id) && !content_changed? && !draft_changed?))
       errors.add(:base, I18n.t('posts.error.permission'))
       raise 'permission'
@@ -132,32 +143,42 @@ def to_mobilis
     }
   end
 
-  ## Return latest date considering children
-  def get_latest_date
-    date = [(children_count <= 0 ? self.updated_at : children.map(&:get_latest_date))].flatten.compact
-    date.sort.last
-  end
-
-  ## Recupera os posts mais recentes dos niveis inferiores aos posts analisados e, então,
-  ## reordena analisando ou as datas dos posts em questão ou a data do "filho/neto" mais recente
-  def self.reorder_by_latest_posts(posts)
-    return posts.sort_by{|post|
-      post.get_latest_date
-    }.reverse
-  end
-
-  def delete_with_dependents
-    children.map(&:delete_with_dependents)
-    remove_all_files
-    self.delete
-  end
+  # deleta o post e todos os seus dependentes
+  # Os métodos abaixo (`get_latest_date`, `delete_with_dependents`, `reorder_by_latest_posts`)
+  # eram auxiliares para a antiga lógica de recursão manual e foram removidos.
+  # - `delete_with_dependents` foi substituído pelo `orphan_strategy: :destroy` da gem ancestry.
+  # - `reorder_by_latest_posts` e `get_latest_date` causavam problemas de N+1 queries.
+  #
+
+  # ## Return latest date considering children
+  # def get_latest_date
+  #   date = [(children_count <= 0 ? self.updated_at : children.map(&:get_latest_date))].flatten.compact
+  #   date.sort.last
+  # end
+
+  # def delete_with_dependents
+  #   children.map(&:delete_with_dependents)
+  #   remove_all_files
+  #   self.delete
+  # end
+
+  # ## Recupera os posts mais recentes dos niveis inferiores aos posts analisados e, então,
+  # ## reordena analisando ou as datas dos posts em questão ou a data do "filho/neto" mais recente
+  # def self.reorder_by_latest_posts(posts)
+  #   return posts.sort_by{|post|
+  #     post.get_latest_date
+  #   }.reverse
+  # end
 
-   # obtain and reorder posts by its "children/grandchildren"
   def reordered_children(user_id, display_mode='three')
     if display_mode == 'list'
       children.where("draft = 'f' OR (draft = 't' AND user_id = ?)", user_id)
     else
-      Post.reorder_by_latest_posts(children.where("draft = 'f' OR (draft = 't' AND user_id = ?)", user_id))
+      #Post.reorder_by_latest_posts(children.where("draft = 'f' OR (draft = 't' AND user_id = ?)", user_id))
+      # A ordenação complexa e custosa (`reorder_by_latest_posts`) foi removida.
+      # Este método agora apenas filtra os filhos (visíveis para o usuário atual),
+      # pois a ordenação da árvore é feita de forma mais eficiente no controller.
+      children.where("draft = 'f' OR (draft = 't' AND user_id = ?)", user_id)
     end
   end
 
@@ -172,10 +193,13 @@ def send_email
     end
   end
 
+  # Ordena posts por última atividade (threads com comentários recentes aparecem primeiro)
+  scope :order_by_ancestry, -> { order(last_activity_at: :desc, id: :desc) }
+
   private
 
     def set_level
-      self.level = parent.level.to_i + 1 unless parent_id.nil?
+      self.level = parent.level.to_i + 1 unless ancestry.nil?
     end
 
     def remove_all_files
@@ -186,22 +210,34 @@ def remove_all_files
     end
 
     def increment_counter
-      Post.increment_counter('children_count', parent_id)
+      Post.increment_counter('children_count', ancestry)
     end
 
     def decrement_counter
-      Post.decrement_counter('children_count', parent_id) unless parent.blank? || parent.try(:children_count) == 0
+      Post.decrement_counter('children_count', ancestry) unless parent.blank? || parent.try(:children_count) == 0
     end
 
     def decrement_counter_draft
-      Post.decrement_counter('children_drafts_count', parent_id) unless parent.blank? || parent.try(:children_drafts_count) == 0 || !draft_was
+      Post.decrement_counter('children_drafts_count', ancestry) unless parent.blank? || parent.try(:children_drafts_count) == 0 || !draft_was
     end
 
     def change_counter_draft
       if draft
-        Post.increment_counter('children_drafts_count', parent_id)
+        Post.increment_counter('children_drafts_count', ancestry)
       else
-        Post.decrement_counter('children_drafts_count', parent_id) unless parent.try(:children_drafts_count) == 0
+        Post.decrement_counter('children_drafts_count', ancestry) unless parent.try(:children_drafts_count) == 0
+      end
+    end
+
+    # Atualiza last_activity_at do post e de todos os ancestrais até a raiz
+    # Exemplo: quando F é criado/editado na árvore A -> C -> F, atualiza F, C e A
+    def update_last_activity
+      current_time = Time.current
+      self.update_column(:last_activity_at, current_time)
+
+      ancestor_ids = self.path_ids - [self.id]
+      unless ancestor_ids.empty?
+        Post.where(id: ancestor_ids).update_all(last_activity_at: current_time)
       end
     end
 
diff --git a/app/views/posts/_post.html.haml b/app/views/posts/_post.html.haml
index 62fb01ea3..4f540a897 100755
--- a/app/views/posts/_post.html.haml
+++ b/app/views/posts/_post.html.haml
@@ -1,7 +1,7 @@
 - user, new_post_class = post.user, ((new_post && new_post.to_i == post.id) ? "new" : "")
 - post_draft = post.draft ? " draft" : ""
 
-- children = post.reordered_children(current_user.id, display_mode)
+
 - editable = ((post.user_id == current_user.id) && (post.children_count == 0 || post.children_drafts_count == post.children_count))
 
 - files    = post.files
@@ -64,8 +64,10 @@
                   %li= button_tag content_tag(:i, nil, class: 'icon-reply'), class: 'btn btn_disabled', disabled: true, :'data-tooltip'=> t('.answer'), :'aria-label'=> t('.answer')
         .forum_post_reply
       - unless display_mode == 'list'
-        - children.each do |child|
-          = render partial: 'post', locals: { post: child, display_mode: display_mode, can_interact: can_interact, can_post: can_post, current_user: current_user, new_post: new_post }
+        -# Ordena filhos por última atividade (comentários recentes aparecem primeiro)
+        - if post.has_children?
+          - post.children.order(last_activity_at: :desc, id: :desc).each do |child|
+            = render partial: 'post', locals: { post: child, display_mode: display_mode, can_interact: can_interact, can_post: can_post, current_user: current_user, new_post: new_post }
   ._line
  
 :javascript
diff --git a/app/views/posts/index.html.haml b/app/views/posts/index.html.haml
index 856261f06..fe83477d3 100644
--- a/app/views/posts/index.html.haml
+++ b/app/views/posts/index.html.haml
@@ -48,7 +48,7 @@
       .new_posts
         #new_post
           = simple_form_for(@post, html: { id: 'new_post_form', :'action-to-edit' => discussion_post_path(@discussion.id, ':id'), :"action-default" => discussion_posts_path(@discussion.id), method: :put, multipart: true }) do |form|
-            = form.hidden_field(:parent_id,  value: '', id: 'discussion_post_parent_id')
+            = form.hidden_field(:ancestry,  value: '', id: 'discussion_post_parent_id')
             = form.hidden_field(:display_mode, value: @display_mode, id: 'display_mode_1')
             = form.hidden_field(:current_page, value: @current_page, id: 'current_page_1')
             = form.text_area(:content)
@@ -85,7 +85,8 @@
 
     .forum_posts_wrapper
       - @hash = { } unless @display_mode == 'list'
-      - @posts = get_page_posts(@posts, @current_page) unless @display_mode == 'list'
+      -# REMOVIDO: get_page_posts não é mais necessário pois @posts já vem paginado do banco via WillPaginate
+      -# - @posts = get_page_posts(@posts, @current_page) unless @display_mode == 'list'
       - @posts.each do |post|
         = render partial: 'post', locals: { post: post, display_mode: @display_mode, can_interact: @can_interact, can_post: @can_post, current_user: @user, new_post: false, number: '', comments: (@acu.try(:comments).count rescue nil)}
 
@@ -98,6 +99,7 @@
     = raw t('posts.post.fv_explain')
 
 
+- ws_config = Rails.application.config_for(:global).fetch(:websocket, {})
 = javascript_include_tag 'ckeditor/init', 'discussions', 'contextual_help/discussion_posts', 'audios', 'pagination', 'tooltip', 'academic_allocation_user'
 
 :javascript
@@ -136,12 +138,12 @@
 
     CKEDITOR_BASEPATH  = "#{request.env['RAILS_RELATIVE_URL_ROOT']}/assets/ckeditor/";
 
-    var websocket_host = "#{YAML::load(File.open("config/global.yml"))[Rails.env.to_s]["websocket"]["host"]}";
-    var websocket_port = "#{YAML::load(File.open("config/global.yml"))[Rails.env.to_s]["websocket"]["port"]}";
-
-    $(".forum_button_attachment").call_fancybox({
-      element_selector: '.focu'
-    });
+    // O carregamento direto do YAML foi substituído pelo `Rails.application.config_for`,
+    // que é a maneira padrão, segura e performática do Rails para acessar configurações.
+    // O `.fetch` garante valores padrão ('localhost', '8080') caso a configuração não exista.
+    var websocket_host = "#{ws_config.fetch(:host, 'localhost')}";
+    var websocket_port = "#{ws_config.fetch(:port, '8080')}";
+    $(".forum_button_attachment").call_fancybox({ element_selector: '.focu' });
 
     var display_list = ("#{escape_once(@display_mode) == 'list'}" == "true");
     var ac = "#{@academic_allocation.id}";
@@ -169,9 +171,9 @@
      ws.onmessage = function (msg) {
       var data = JSON.parse(msg.data);
       var post_table   = $("article#"+data.post_id);
-      var parent_table = $("article#"+data.parent_id);
+      var parent_table = $("article#"+data.ancestry);
       // recover grandparent if has parent, but it doesn't exists at view (so it must render all tree of posts) and isn't list view and it is at first page
-      var grandparent  = (data.parent_id != null && !parent_table.length && !display_list && (1 == parseInt("#{escape_once(@current_page)}")));
+      var grandparent  = (data.ancestry != null && !parent_table.length && !display_list && (1 == parseInt("#{escape_once(@current_page)}")));
 
       $.get("#{discussion_post_path(@discussion.id, ':id', researcher: @researcher)}".replace(':id', data.post_id), {new_post: true, grandparent: grandparent}, function(data2){
         if (!!post_table.length) // if post exists
@@ -181,7 +183,7 @@
             $(parent_table.find("._cell.forum_post_content .forum_post_wrapper")[0]).after(data2);
             parent_table.find(".forum_post_buttons:first").find(".update_post:first, .forum_button_attachment:first, .btn_caution:first").remove();
           }else // if hasn't parent and is at the same page or is list view
-            if (data.parent_id == null && (1 == parseInt("#{escape_once(@current_page)}")) || !!display_list || !!grandparent)
+            if (data.ancestry == null && (1 == parseInt("#{escape_once(@current_page)}")) || !!display_list || !!grandparent)
               $(".forum_posts_wrapper").prepend(data2);
 
         add_post_count_warning("#{escape_once(@current_page)}");
@@ -202,13 +204,13 @@
         content = '<p>'+content+'</p>';
       }
 
-      // get parent_id information
+      // get ancestry information
       if (form.attr("method") == "POST")
         var parent_table = $($(this).parents("article")[0]);
       if (parent_table == undefined)
-        var parent_id = null;
+        var ancestry = null;
       else
-        var parent_id = parent_table.attr("id");
+        var ancestry = parent_table.attr("id");
 
       var draft = $(this).data('draft');
 
@@ -258,7 +260,7 @@
             ws.send(JSON.stringify({
               msg: content,
               post_id: data.post_id,
-              parent_id: data.parent_id,
+              ancestry: data.ancestry,
               academic_allocation_id: ac
             }));
           loadFocus();
@@ -357,7 +359,7 @@
         ws.send(JSON.stringify({
           msg: data.content,
           post_id: data.post_id,
-          parent_id: data.parent_id,
+          ancestry: data.ancestry,
           academic_allocation_id: data.ac_id
         }));
       }).fail(function(){
diff --git a/config/application.rb b/config/application.rb
index 599dbd24e..6c1299bf2 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -29,6 +29,8 @@ class Application < Rails::Application
     # :all can be used as a placeholder for all plugins not explicitly named.
     # config.plugins = [ :exception_notification, :ssl_requirement, :all ]
 
+    # config.active_record.record_timestamps = false
+    
     # Activate observers that should always be running.
     # config.active_record.observers = :cacher, :garbage_collector, :forum_observer
     #config.middleware.use "PDFKit::Middleware", :print_media_type => true
diff --git a/config/environment.rb b/config/environment.rb
index 6829c6a20..7ab56aa49 100644
--- a/config/environment.rb
+++ b/config/environment.rb
@@ -88,4 +88,4 @@
 
 # número máximo de turmas exibidas sem expansão da div
 Max_Groups_Shown_Filter = 30 # no filtro
-Max_Groups_Shown_Tags 	= 15 # nas tags
\ No newline at end of file
+Max_Groups_Shown_Tags 	= 15 # nas tags
diff --git a/db/migrate/20251201180714_add_ancestry_column_to_discussion_posts.rb b/db/migrate/20251201180714_add_ancestry_column_to_discussion_posts.rb
new file mode 100644
index 000000000..344a75964
--- /dev/null
+++ b/db/migrate/20251201180714_add_ancestry_column_to_discussion_posts.rb
@@ -0,0 +1,9 @@
+ # Dentro de db/migrate/SEU_NOVO_ARQUIVO_DE_MIGRATION.rb
+  class AddAncestryColumnToDiscussionPosts < ActiveRecord::Migration[5.1] # Mantenha a versão do Rails
+
+    def change
+     add_column :discussion_posts, :ancestry, :string
+      add_index :discussion_posts, :ancestry
+    end
+  end
+
diff --git a/db/migrate/20251209113048_add_last_activity_at_to_discussion_posts.rb b/db/migrate/20251209113048_add_last_activity_at_to_discussion_posts.rb
new file mode 100644
index 000000000..1d787064f
--- /dev/null
+++ b/db/migrate/20251209113048_add_last_activity_at_to_discussion_posts.rb
@@ -0,0 +1,31 @@
+class AddLastActivityAtToDiscussionPosts < ActiveRecord::Migration[5.1]
+  def up
+    # Adiciona coluna para armazenar timestamp da última atividade na subárvore
+    add_column :discussion_posts, :last_activity_at, :datetime
+
+#     # Popula a coluna com dados existentes
+#     # Para cada post, busca o updated_at mais recente entre ele e seus descendentes
+#     say_with_time "Populando last_activity_at para posts existentes..." do
+#       execute <<-SQL
+        # UPDATE discussion_posts AS post
+        # SET last_activity_at = COALESCE(
+        #   (
+        #     SELECT MAX(descendants.updated_at)
+        #     FROM discussion_posts AS descendants
+        #     WHERE descendants.ancestry LIKE post.id || '/%'
+        #        OR descendants.id = post.id
+        #   ),
+        #   post.updated_at
+        # )
+#       SQL
+#     end
+
+    # Índice para otimizar ordenação por última atividade
+    add_index :discussion_posts, :last_activity_at
+  end
+
+  def down
+    remove_index :discussion_posts, :last_activity_at
+    remove_column :discussion_posts, :last_activity_at
+  end
+end
diff --git a/db/migrate/20251218112205_remove_parent_id_from_discussion_posts.rb b/db/migrate/20251218112205_remove_parent_id_from_discussion_posts.rb
new file mode 100644
index 000000000..a60127cdc
--- /dev/null
+++ b/db/migrate/20251218112205_remove_parent_id_from_discussion_posts.rb
@@ -0,0 +1,13 @@
+class RemoveParentIdFromDiscussionPosts < ActiveRecord::Migration[5.1]
+  def up
+    # Remove o index primeiro
+    remove_index :discussion_posts, name: :parent_id_idx if index_exists?(:discussion_posts, :parent_id, name: :parent_id_idx)
+    # Depois remove a coluna
+    remove_column :discussion_posts, :parent_id
+  end
+
+  def down
+    add_column :discussion_posts, :parent_id, :integer
+    add_index :discussion_posts, :parent_id, name: :parent_id_idx
+  end
+end