diff --git a/app/models/activity.rb b/app/models/activity.rb
index 263f77c79..e9667dd64 100644
--- a/app/models/activity.rb
+++ b/app/models/activity.rb
@@ -6,7 +6,7 @@ class Activity < ApplicationRecord
   validates :action, presence: true, inclusion: { in: %w[create update destroy] }
   validates :project, presence: true
   validates :user, presence: true
-  validates :subject, presence: true, subject_changed: true
+  validates :subject, presence: true, changed: true
 
   serialize :subject_changes, Hash
 
diff --git a/app/models/story.rb b/app/models/story.rb
index 2ab3e3e10..063466f3e 100644
--- a/app/models/story.rb
+++ b/app/models/story.rb
@@ -102,10 +102,10 @@ def from_csv_row(row)
   enumerize :story_type, in: STORY_TYPES, predicates: true, scope: true
   validates :project, presence: true
   validates :title, presence: true
-  validates :requested_by_id, user_belongs_to_project: true
-  validates :owned_by_id, user_belongs_to_project: true
+  validates :requested_by_id, belongs_to_project: true
+  validates :owned_by_id, belongs_to_project: true
   validates :story_type, presence: true
-  validates :estimate, central_estimate: true, allow_nil: true
+  validates :estimate, estimate: true, allow_nil: true
   validate :validate_non_estimable_story
 
   def self.csv_headers
diff --git a/app/validators/belongs_to_project_validator.rb b/app/validators/belongs_to_project_validator.rb
new file mode 100644
index 000000000..dcc56637f
--- /dev/null
+++ b/app/validators/belongs_to_project_validator.rb
@@ -0,0 +1,11 @@
+class BelongsToProjectValidator < ActiveModel::EachValidator
+  # Checks that the parameter being validated represents a User#id that
+  # is a member of the object.project
+  def validate_each(record, attribute, value)
+    return if record.project.blank? || value.blank?
+
+    return if record.project.user_ids.include?(value)
+
+    record.errors.add(attribute, message: 'user is not a member of this project')
+  end
+end
diff --git a/app/validators/central_estimate_validator.rb b/app/validators/central_estimate_validator.rb
deleted file mode 100644
index 76045605e..000000000
--- a/app/validators/central_estimate_validator.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-class CentralEstimateValidator < ActiveModel::EachValidator
-  # TODO: Change the name to EstimateValidator when remove support gem
-  # Checks that the estimate being validated is valid for record.project
-  def validate_each(record, attribute, value)
-    if record.project
-      unless record.project.point_values.include?(value)
-        record.errors.add(attribute, message: 'is not an allowed value for this project')
-      end
-    end
-  end
-end
diff --git a/app/validators/subject_changed_validator.rb b/app/validators/changed_validator.rb
similarity index 51%
rename from app/validators/subject_changed_validator.rb
rename to app/validators/changed_validator.rb
index 6bc83bc92..6f45ed03d 100644
--- a/app/validators/subject_changed_validator.rb
+++ b/app/validators/changed_validator.rb
@@ -1,9 +1,8 @@
-# TODO: Change the class name to ChangedValidator when remove cm42-central-support gem
-class SubjectChangedValidator < ActiveModel::EachValidator
+class ChangedValidator < ActiveModel::EachValidator
   def validate_each(record, attribute, value)
-    return if record.action != 'update' 
+    return if record.action != 'update'
     return if value&.valid? && value&.saved_changes.present?
-      
+
     record.errors.add(attribute, message: (options[:message] || "Record didn't change"))
   end
 end
diff --git a/app/validators/estimate_validator.rb b/app/validators/estimate_validator.rb
new file mode 100644
index 000000000..4d7abb386
--- /dev/null
+++ b/app/validators/estimate_validator.rb
@@ -0,0 +1,10 @@
+class EstimateValidator < ActiveModel::EachValidator
+  # Checks that the estimate being validated is valid for record.project
+  def validate_each(record, attribute, value)
+    return if record.project.blank?
+
+    return if record.project.point_values.include?(value)
+
+    record.errors.add(attribute, message: 'is not an allowed value for this project')
+  end
+end
diff --git a/app/validators/user_belongs_to_project_validator.rb b/app/validators/user_belongs_to_project_validator.rb
deleted file mode 100644
index 20c6a9ac4..000000000
--- a/app/validators/user_belongs_to_project_validator.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-class UserBelongsToProjectValidator < ActiveModel::EachValidator
-  # TODO: Change de name class to BelongsToProjectValidator when remove support gem
-  # Checks that the parameter being validated represents a User#id that
-  # is a member of the object.project
-  def validate_each(record, attribute, value)
-    if record.project && !value.nil?
-      unless record.project.user_ids.include?(value)
-        record.errors.add(attribute, message: 'user is not a member of this project')
-      end
-    end
-  end
-end