diff --git a/app/models/notification.rb b/app/models/notification.rb
index d0a4f3919..1009b9dfe 100644
--- a/app/models/notification.rb
+++ b/app/models/notification.rb
@@ -2,14 +2,10 @@
 
 class Notification < ApplicationRecord
   has_many :user_notifications, inverse_of: :notification, dependent: :destroy
-  has_many :users, through: :user_notifications
-  belongs_to :generator_user, class_name: 'User', optional: true
 
   include Noticed::Model
   belongs_to :recipient, polymorphic: true
 
-  enum type_of: Extends::NOTIFICATIONS_TYPES
-
   private
 
   def can_send_to_user?(_user)
diff --git a/config/initializers/extends.rb b/config/initializers/extends.rb
index 7d1523c28..41e511b68 100644
--- a/config/initializers/extends.rb
+++ b/config/initializers/extends.rb
@@ -14,13 +14,6 @@ class Extends
 
   # Extends enum types. Should not be freezed, as modules might append to this.
   # !!!Check all addons for the correct order!!!
-  # DEPRECATED 'system_message' in (SCI-2952, kept b/c of integer enums)
-  NOTIFICATIONS_TYPES = { assignment: 0,
-                          recent_changes: 1,
-                          system_message: 2, # DEPRECATED
-                          deliver: 5,
-                          deliver_error: 7 }
-
   TASKS_STATES = { uncompleted: 0,
                    completed: 1 }
 
diff --git a/db/migrate/20231011103114_migrate_notification_to_noticed.rb b/db/migrate/20231011103114_migrate_notification_to_noticed.rb
index 843aebfef..888d3d259 100644
--- a/db/migrate/20231011103114_migrate_notification_to_noticed.rb
+++ b/db/migrate/20231011103114_migrate_notification_to_noticed.rb
@@ -9,10 +9,10 @@ class MigrateNotificationToNoticed < ActiveRecord::Migration[7.0]
     add_column :notifications, :recipient_type, :string
 
     type_mapping = {
-      'assignment' => 'ActivityNotification',
-      'recent_changes' => 'GeneralNotification',
-      'deliver' => 'DeliveryNotification',
-      'deliver_error' => 'DeliveryNotification'
+      0 => 'ActivityNotification',
+      1 => 'GeneralNotification',
+      5 => 'DeliveryNotification',
+      7 => 'DeliveryNotification'
     }
 
     UserNotification.includes(:notification).find_each do |user_notification|
@@ -26,8 +26,7 @@ class MigrateNotificationToNoticed < ActiveRecord::Migration[7.0]
         legacy: true
       }
 
-      params[:error] = notification.type_of == 'deliver_error' if new_type == 'DeliveryNotification'
-
+      params[:error] = notification.type_of == 7 if new_type == 'DeliveryNotification'
       notification.update(
         params: params,
         type: new_type,