diff --git a/app/controllers/concerns/two_factor_authenticatable_methods.rb b/app/controllers/concerns/two_factor_authenticatable_methods.rb
index 56f4cc02a30..bcfee78cc87 100644
--- a/app/controllers/concerns/two_factor_authenticatable_methods.rb
+++ b/app/controllers/concerns/two_factor_authenticatable_methods.rb
@@ -33,7 +33,7 @@ def handle_valid_verification_for_authentication_context(auth_method:)
     mark_user_session_authenticated(auth_method:, authentication_type: :valid_2fa)
     disavowal_event, disavowal_token = create_user_event_with_disavowal(:sign_in_after_2fa)
 
-    if IdentityConfig.store.feature_new_device_alert_aggregation_enabled && new_device?
+    if new_device?
       if current_user.sign_in_new_device_at.blank?
         if sign_in_notification_timeframe_expired_event.present?
           current_user.update(
diff --git a/app/mailers/user_mailer.rb b/app/mailers/user_mailer.rb
index b5a097c61d2..74064a42085 100644
--- a/app/mailers/user_mailer.rb
+++ b/app/mailers/user_mailer.rb
@@ -112,19 +112,6 @@ def personal_key_sign_in(disavowal_token:)
     end
   end
 
-  def new_device_sign_in(date:, location:, device_name:, disavowal_token:)
-    with_user_locale(user) do
-      @login_date = date
-      @login_location = location
-      @device_name = device_name
-      @disavowal_token = disavowal_token
-      mail(
-        to: email_address.email,
-        subject: t('user_mailer.new_device_sign_in.subject', app_name: APP_NAME),
-      )
-    end
-  end
-
   # @param [Array<Hash>] events Array of sign-in Event records (event types "sign_in_before_2fa",
   # "sign_in_after_2fa", "sign_in_unsuccessful_2fa")
   # @param [String] disavowal_token Token to generate URL for disavowing event
diff --git a/app/services/user_alerts/alert_user_about_new_device.rb b/app/services/user_alerts/alert_user_about_new_device.rb
index 28d70f4172f..90c17b7340f 100644
--- a/app/services/user_alerts/alert_user_about_new_device.rb
+++ b/app/services/user_alerts/alert_user_about_new_device.rb
@@ -2,26 +2,8 @@
 
 module UserAlerts
   class AlertUserAboutNewDevice
-    def self.call(event:, device:, disavowal_token:)
-      return if IdentityConfig.store.feature_new_device_alert_aggregation_enabled
-      device_decorator = DeviceDecorator.new(device)
-      login_location = device_decorator.last_sign_in_location_and_ip
-      device_name = device_decorator.nice_name
-
-      event.user.confirmed_email_addresses.each do |email_address|
-        UserMailer.with(user: event.user, email_address: email_address).new_device_sign_in(
-          date: device.last_used_at.in_time_zone('Eastern Time (US & Canada)').
-            strftime('%B %-d, %Y %H:%M Eastern Time'),
-          location: login_location,
-          device_name: device_name,
-          disavowal_token: disavowal_token,
-        ).deliver_now_or_later
-      end
-    end
-
     def self.schedule_alert(event:)
-      return if !IdentityConfig.store.feature_new_device_alert_aggregation_enabled ||
-                event.user.sign_in_new_device_at.present?
+      return if event.user.sign_in_new_device_at.present?
       event.user.update(sign_in_new_device_at: event.created_at)
     end
 
@@ -53,10 +35,8 @@ def self.send_alert(user:, disavowal_event:, disavowal_token:)
     end
 
     def self.sign_in_events_start_time(user:)
-      # Avoid scenarios where stale events may be reflected in the time since sign in:
-      #
-      # 1. The feature is enabled for a short time in a deployed environment before being disabled
-      # 2. In local development, the server is not always active and the job may not run until later
+      # Avoid scenarios where stale events may be reflected in the time since sign in, such as if
+      # the server is not always active and the job may not run until later.
       #
       # Typically, it's guaranteed that even in the worst-case of a sign-in occurring immediately
       # after a scheduled job run, it should take no longer than twice the scheduled delay. A small
diff --git a/app/services/user_event_creator.rb b/app/services/user_event_creator.rb
index 106cd0de154..4c7cd351596 100644
--- a/app/services/user_event_creator.rb
+++ b/app/services/user_event_creator.rb
@@ -84,7 +84,6 @@ def create_event_for_new_device(event_type:, user:, disavowal_token:)
         event, disavowal_token = create_user_event_with_disavowal(event_type, user, device)
         [device, event, disavowal_token]
       end
-      send_new_device_notification(event:, device:, disavowal_token:)
       [event, disavowal_token]
     else
       Device.transaction do
@@ -111,10 +110,6 @@ def create_device_for_user(user)
     )
   end
 
-  def send_new_device_notification(event:, device:, disavowal_token:)
-    UserAlerts::AlertUserAboutNewDevice.call(event:, device:, disavowal_token:)
-  end
-
   # @return [Array(Event, String)] an (event, disavowal_token) tuple
   def create_event_for_device(event_type:, user:, device:, disavowal_token: nil)
     disavowal_token_fingerprint = if disavowal_token
diff --git a/app/views/user_mailer/new_device_sign_in.html.erb b/app/views/user_mailer/new_device_sign_in.html.erb
deleted file mode 100644
index ae3cd4c2b51..00000000000
--- a/app/views/user_mailer/new_device_sign_in.html.erb
+++ /dev/null
@@ -1,41 +0,0 @@
-<table class="spacer">
-  <tbody>
-    <tr>
-      <td class="s10" height="10px">
-        &nbsp;
-      </td>
-    </tr>
-  </tbody>
-</table>
-
-<table class="hr">
-  <tr>
-    <th>
-      &nbsp;
-    </th>
-  </tr>
-</table>
-
-<p>
-  <%= t(
-        'user_mailer.new_device_sign_in.info',
-        app_name: APP_NAME,
-      ) %>    
-</p>
-
-<br/>
-
-<p><strong><%= @login_date %><br/><%= @login_location %>, <%= @device_name %></strong></p>
-
-<p>
-  <%= t(
-        'user_mailer.new_device_sign_in.help_html',
-        app_name_html: link_to(APP_NAME, IdentityConfig.store.mailer_domain_name, class: 'gray'),
-        disavowal_link_html: link_to(
-          t('.disavowal_link'),
-          event_disavowal_url(disavowal_token: @disavowal_token),
-        ),
-        help_link_html: link_to(t('user_mailer.help_link_text'), MarketingSite.help_url),
-        contact_link_html: link_to(t('user_mailer.contact_link_text'), MarketingSite.contact_url),
-      ) %>
-</p>
diff --git a/config/application.yml.default b/config/application.yml.default
index d21d14aaade..2f4e0f56e17 100644
--- a/config/application.yml.default
+++ b/config/application.yml.default
@@ -64,20 +64,20 @@ country_phone_number_overrides: '{}'
 database_host: ''
 database_name: ''
 database_password: ''
+database_pool_idp: 5
 database_read_replica_host: ''
 database_readonly_password: ''
 database_readonly_username: ''
-database_username: ''
-database_worker_jobs_host: ''
-database_worker_jobs_name: ''
-database_worker_jobs_password: ''
-database_worker_jobs_username: ''
-database_pool_idp: 5
 database_socket: ''
 database_sslmode: 'verify-full'
 database_statement_timeout: 2_500
 database_timeout: 5_000
+database_username: ''
+database_worker_jobs_host: ''
+database_worker_jobs_name: ''
+database_worker_jobs_password: ''
 database_worker_jobs_sslmode: 'verify-full'
+database_worker_jobs_username: ''
 deleted_user_accounts_report_configs: '[]'
 deliver_mail_async: false
 development_mailer_deliver_method: letter_opener
@@ -115,7 +115,6 @@ enable_usps_verification: true
 event_disavowal_expiration_hours: 240
 feature_idv_force_gpo_verification_enabled: false
 feature_idv_hybrid_flow_enabled: true
-feature_new_device_alert_aggregation_enabled: true
 geo_data_file_path: 'geo_data/GeoLite2-City.mmdb'
 get_usps_proofing_results_job_cron: '0/30 * * * *'
 get_usps_proofing_results_job_reprocess_delay_minutes: 5
@@ -457,7 +456,6 @@ production:
   email_registrations_per_ip_track_only_mode: true
   enable_test_routes: false
   enable_usps_verification: false
-  feature_new_device_alert_aggregation_enabled: false
   hmac_fingerprinter_key:
   hmac_fingerprinter_key_queue: '[]'
   idv_sp_required: true
diff --git a/config/initializers/job_configurations.rb b/config/initializers/job_configurations.rb
index dc89d3f0dad..9e00efaa556 100644
--- a/config/initializers/job_configurations.rb
+++ b/config/initializers/job_configurations.rb
@@ -29,15 +29,11 @@
         args: -> { [Time.zone.now] },
       },
       # Send new device alert notifications
-      create_new_device_alert_send_emails: (
-        if IdentityConfig.store.feature_new_device_alert_aggregation_enabled
-          {
-            class: 'CreateNewDeviceAlert',
-            cron: cron_5m,
-            args: -> { [Time.zone.now] },
-          }
-        end
-      ),
+      create_new_device_alert_send_emails: {
+        class: 'CreateNewDeviceAlert',
+        cron: cron_5m,
+        args: -> { [Time.zone.now] },
+      },
       # Send Total Monthly Auths Report to S3
       total_monthly_auths: {
         class: 'Reports::TotalMonthlyAuthsReport',
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 6de2c54883a..f1a3b37a92f 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1890,10 +1890,6 @@ user_mailer.new_device_sign_in_before_2fa.info_p2: If you recognize this activit
 user_mailer.new_device_sign_in_before_2fa.info_p3_html: Two-factor authentication protects your account from unauthorized access. If this wasn’t you, %{reset_password_link_html} immediately.
 user_mailer.new_device_sign_in_before_2fa.reset_password: reset your password
 user_mailer.new_device_sign_in_before_2fa.subject: New sign-in with your %{app_name} account
-user_mailer.new_device_sign_in.disavowal_link: reset your password
-user_mailer.new_device_sign_in.help_html: If you did not make this change, %{disavowal_link_html}. For more help, please visit the %{app_name_html} %{help_link_html} or %{contact_link_html}.
-user_mailer.new_device_sign_in.info: Your %{app_name} account was just used to sign in on a new device.
-user_mailer.new_device_sign_in.subject: New sign-in with your %{app_name} account
 user_mailer.password_changed.disavowal_link: reset your password
 user_mailer.password_changed.help_html: If you did not make this change, %{disavowal_link_html}. For more help, please visit the %{app_name_html} %{help_link_html} or %{contact_link_html}.
 user_mailer.password_changed.intro_html: You have a new password for your %{app_name_html} account.
diff --git a/config/locales/es.yml b/config/locales/es.yml
index 6ecef7c4140..2d5bcae878a 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -1902,10 +1902,6 @@ user_mailer.new_device_sign_in_before_2fa.info_p2: Si reconoce esta actividad, n
 user_mailer.new_device_sign_in_before_2fa.info_p3_html: La autenticación de dos factores protege su cuenta contra un acceso no autorizado. Si no fue usted, %{reset_password_link_html}.
 user_mailer.new_device_sign_in_before_2fa.reset_password: restablezca de inmediato su contraseña.
 user_mailer.new_device_sign_in_before_2fa.subject: Nuevo inicio de sesión con su cuenta de %{app_name}
-user_mailer.new_device_sign_in.disavowal_link: restablezca su contraseña
-user_mailer.new_device_sign_in.help_html: Si usted no hizo este cambio, %{disavowal_link_html}. Para obtener más ayuda, visite %{app_name_html} %{help_link_html} o %{contact_link_html}.
-user_mailer.new_device_sign_in.info: Su cuenta de %{app_name} acaba de ser usada para iniciar sesión en un nuevo dispositivo.
-user_mailer.new_device_sign_in.subject: Nuevo inicio de sesión con su cuenta de %{app_name}
 user_mailer.password_changed.disavowal_link: restablezca su contraseña
 user_mailer.password_changed.help_html: Si usted no hizo este cambio, %{disavowal_link_html}. Para obtener más ayuda, visite %{app_name_html} %{help_link_html} o %{contact_link_html}.
 user_mailer.password_changed.intro_html: Tiene una contraseña nueva para su cuenta de %{app_name_html}.
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index f7cb0fdc66e..a1489bc0f48 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -1890,10 +1890,6 @@ user_mailer.new_device_sign_in_before_2fa.info_p2: Si vous reconnaissez cette ac
 user_mailer.new_device_sign_in_before_2fa.info_p3_html: L’authentification à deux facteurs protège votre compte des accès non autorisés. Si vous n’êtes pas à l’origine de cette action, %{reset_password_link_html}.
 user_mailer.new_device_sign_in_before_2fa.reset_password: veuillez réinitialiser immédiatement votre mot de passe.
 user_mailer.new_device_sign_in_before_2fa.subject: Nouvelle connexion avec votre compte %{app_name}
-user_mailer.new_device_sign_in.disavowal_link: réinitialisez votre mot de passe
-user_mailer.new_device_sign_in.help_html: Si vous n’avez pas effectué ce changement, %{disavowal_link_html}. Pour plus d’aide, veuillez visiter le %{help_link_html} de %{app_name_html} ou %{contact_link_html}.
-user_mailer.new_device_sign_in.info: Votre compte %{app_name} vient d’être utilisé pour une connexion sur un nouvel appareil.
-user_mailer.new_device_sign_in.subject: Nouvelle connexion avec votre compte %{app_name}
 user_mailer.password_changed.disavowal_link: réinitialisez votre mot de passe
 user_mailer.password_changed.help_html: Si vous n’avez pas effectué ce changement, %{disavowal_link_html}. Pour plus d’aide, veuillez visiter le %{help_link_html} de %{app_name_html} ou %{contact_link_html}.
 user_mailer.password_changed.intro_html: Vous avez un nouveau mot de passe pour votre compte %{app_name_html}.
diff --git a/config/locales/zh.yml b/config/locales/zh.yml
index 0122bd5cb22..316555349c5 100644
--- a/config/locales/zh.yml
+++ b/config/locales/zh.yml
@@ -1903,10 +1903,6 @@ user_mailer.new_device_sign_in_before_2fa.info_p2: 如果你知道该活动，
 user_mailer.new_device_sign_in_before_2fa.info_p3_html: 双重身份验证保护你账户不受未经授权的访问。如果不是你，请马上 %{reset_password_link_html}.
 user_mailer.new_device_sign_in_before_2fa.reset_password: 重设密码
 user_mailer.new_device_sign_in_before_2fa.subject: 你 %{app_name} 账户有新的登录
-user_mailer.new_device_sign_in.disavowal_link: 重设你的密码
-user_mailer.new_device_sign_in.help_html: 如果你没做此更改， %{disavowal_link_html}。要得到更多帮助，请访问 %{app_name_html} %{help_link_html} 或者 %{contact_link_html}。
-user_mailer.new_device_sign_in.info: 你的 %{app_name} 帐号刚刚在一个新设备上用于登录。
-user_mailer.new_device_sign_in.subject: 用你 %{app_name} 账户进行的新登录
 user_mailer.password_changed.disavowal_link: 重设你的密码
 user_mailer.password_changed.help_html: 如果你没做此更改， %{disavowal_link_html}。要得到更多帮助，请访问 %{app_name_html} %{help_link_html} 或者 %{contact_link_html}。
 user_mailer.password_changed.intro_html: 你的 %{app_name_html} 账户有了新密码。
diff --git a/lib/identity_config.rb b/lib/identity_config.rb
index 9412d21a65f..cce2257722a 100644
--- a/lib/identity_config.rb
+++ b/lib/identity_config.rb
@@ -136,7 +136,6 @@ def self.store
     config.add(:event_disavowal_expiration_hours, type: :integer)
     config.add(:feature_idv_force_gpo_verification_enabled, type: :boolean)
     config.add(:feature_idv_hybrid_flow_enabled, type: :boolean)
-    config.add(:feature_new_device_alert_aggregation_enabled, type: :boolean)
     config.add(:geo_data_file_path, type: :string)
     config.add(:get_usps_proofing_results_job_cron, type: :string)
     config.add(:get_usps_proofing_results_job_reprocess_delay_minutes, type: :integer)
diff --git a/spec/controllers/concerns/two_factor_authenticatable_methods_spec.rb b/spec/controllers/concerns/two_factor_authenticatable_methods_spec.rb
index f1dd1b2ad14..f14f9ec9c32 100644
--- a/spec/controllers/concerns/two_factor_authenticatable_methods_spec.rb
+++ b/spec/controllers/concerns/two_factor_authenticatable_methods_spec.rb
@@ -65,10 +65,9 @@
       context 'when authenticating without new device sign in' do
         let(:user) { create(:user) }
 
-        context 'when alert aggregation feature is disabled' do
+        context 'with an existing device' do
           before do
-            allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-              and_return(false)
+            allow(controller).to receive(:new_device?).and_return(false)
           end
 
           it 'does not send an alert' do
@@ -78,79 +77,60 @@
           end
         end
 
-        context 'when alert aggregation feature is enabled' do
+        context 'with a new device' do
           before do
-            allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-              and_return(true)
+            allow(controller).to receive(:new_device?).and_return(true)
           end
 
-          context 'with an existing device' do
-            before do
-              allow(controller).to receive(:new_device?).and_return(false)
+          it 'sends the new device alert using 2fa event date' do
+            expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert) do |**args|
+              expect(user.reload.sign_in_new_device_at.change(usec: 0)).to eq(
+                args[:disavowal_event].created_at.change(usec: 0),
+              )
+              expect(args[:user]).to eq(user)
+              expect(args[:disavowal_event]).to be_kind_of(Event)
+              expect(args[:disavowal_token]).to be_kind_of(String)
             end
+            result
+          end
 
-            it 'does not send an alert' do
-              expect(UserAlerts::AlertUserAboutNewDevice).to_not receive(:send_alert)
-
+          context 'sign_in_notification_timeframe_expired missing' do
+            it 'tracks analytics event for missing timeframe_expired' do
+              stub_analytics
               result
+
+              expect(@analytics).to have_logged_event(
+                :sign_in_notification_timeframe_expired_absent,
+              )
             end
           end
 
-          context 'with a new device' do
+          context 'sign_in_notification_timeframe_expired present' do
             before do
-              allow(controller).to receive(:new_device?).and_return(true)
+              create(
+                :event,
+                user:,
+                event_type: :sign_in_notification_timeframe_expired,
+                created_at: 10.minutes.ago,
+              )
             end
 
-            it 'sends the new device alert using 2fa event date' do
-              expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert) do |**args|
-                expect(user.reload.sign_in_new_device_at.change(usec: 0)).to eq(
-                  args[:disavowal_event].created_at.change(usec: 0),
-                )
-                expect(args[:user]).to eq(user)
-                expect(args[:disavowal_event]).to be_kind_of(Event)
-                expect(args[:disavowal_token]).to be_kind_of(String)
-              end
-              result
+            around do |ex|
+              freeze_time { ex.run }
             end
 
-            context 'sign_in_notification_timeframe_expired missing' do
-              it 'tracks analytics event for missing timeframe_expired' do
-                stub_analytics
-                result
-
-                expect(@analytics).to have_logged_event(
-                  :sign_in_notification_timeframe_expired_absent,
-                )
-              end
-            end
-
-            context 'sign_in_notification_timeframe_expired present' do
-              before do
-                create(
-                  :event,
-                  user:,
-                  event_type: :sign_in_notification_timeframe_expired,
-                  created_at: 10.minutes.ago,
+            it 'creates a new user event with disavowal' do
+              expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert) do
+                expect(user.reload.sign_in_new_device_at.change(usec: 0)).to eq(
+                  10.minutes.ago,
                 )
               end
+              stub_analytics
+              result
 
-              around do |ex|
-                freeze_time { ex.run }
-              end
-
-              it 'creates a new user event with disavowal' do
-                expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert) do
-                  expect(user.reload.sign_in_new_device_at.change(usec: 0)).to eq(
-                    10.minutes.ago,
-                  )
-                end
-                stub_analytics
-                result
-
-                expect(@analytics).to_not have_logged_event(
-                  :sign_in_notification_timeframe_expired_absent,
-                )
-              end
+              expect(@analytics).to_not have_logged_event(
+                :sign_in_notification_timeframe_expired_absent,
+              )
             end
           end
         end
@@ -159,10 +139,9 @@
       context 'when authenticating with new device sign in' do
         let(:user) { create(:user, sign_in_new_device_at: Time.zone.now) }
 
-        context 'when alert aggregation feature is disabled' do
+        context 'with an existing device' do
           before do
-            allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-              and_return(false)
+            allow(controller).to receive(:new_device?).and_return(false)
           end
 
           it 'does not send an alert' do
@@ -172,35 +151,16 @@
           end
         end
 
-        context 'when alert aggregation feature is enabled' do
+        context 'with a new device' do
           before do
-            allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-              and_return(true)
+            allow(controller).to receive(:new_device?).and_return(true)
           end
 
-          context 'with an existing device' do
-            before do
-              allow(controller).to receive(:new_device?).and_return(false)
-            end
+          it 'sends the new device alert' do
+            expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert).
+              with(user:, disavowal_event: kind_of(Event), disavowal_token: kind_of(String))
 
-            it 'does not send an alert' do
-              expect(UserAlerts::AlertUserAboutNewDevice).to_not receive(:send_alert)
-
-              result
-            end
-          end
-
-          context 'with a new device' do
-            before do
-              allow(controller).to receive(:new_device?).and_return(true)
-            end
-
-            it 'sends the new device alert' do
-              expect(UserAlerts::AlertUserAboutNewDevice).to receive(:send_alert).
-                with(user:, disavowal_event: kind_of(Event), disavowal_token: kind_of(String))
-
-              result
-            end
+            result
           end
         end
       end
diff --git a/spec/features/event_disavowal_spec.rb b/spec/features/event_disavowal_spec.rb
index 4c0b96a7fbf..0259a8ad3f7 100644
--- a/spec/features/event_disavowal_spec.rb
+++ b/spec/features/event_disavowal_spec.rb
@@ -3,65 +3,57 @@
 RSpec.feature 'disavowing an action' do
   let(:user) { create(:user, :fully_registered, :with_personal_key) }
 
-  context 'with aggregated sign-in notifications enabled' do
-    before do
-      allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-        and_return(true)
-      user.devices << create(:device)
-    end
+  scenario 'disavowing a sign-in after 2fa' do
+    sign_in_live_with_2fa(user)
+    Capybara.reset_session!
 
-    scenario 'disavowing a sign-in after 2fa' do
-      sign_in_live_with_2fa(user)
-      Capybara.reset_session!
+    disavow_last_action_and_reset_password
+  end
 
-      disavow_last_action_and_reset_password
+  scenario 'disavowing a sign-in before 2fa' do
+    travel_to (IdentityConfig.store.new_device_alert_delay_in_minutes + 1).minutes.ago do
+      sign_in_user(user)
     end
 
-    scenario 'disavowing a sign-in before 2fa' do
-      travel_to (IdentityConfig.store.new_device_alert_delay_in_minutes + 1).minutes.ago do
-        sign_in_user(user)
-      end
+    Capybara.reset_session!
+    CreateNewDeviceAlert.new.perform(Time.zone.now)
 
-      Capybara.reset_session!
-      CreateNewDeviceAlert.new.perform(Time.zone.now)
+    disavow_last_action_and_reset_password
+  end
 
-      disavow_last_action_and_reset_password
+  scenario 'disavowing a sign-in after 2fa after new device timeframe expired' do
+    travel_to (IdentityConfig.store.new_device_alert_delay_in_minutes + 1).minutes.ago do
+      sign_in_user(user)
     end
 
-    scenario 'disavowing a sign-in after 2fa after new device timeframe expired' do
-      travel_to (IdentityConfig.store.new_device_alert_delay_in_minutes + 1).minutes.ago do
-        sign_in_user(user)
-      end
-
-      CreateNewDeviceAlert.new.perform(Time.zone.now)
+    CreateNewDeviceAlert.new.perform(Time.zone.now)
 
-      expect_delivered_email_count(1)
-      expect_delivered_email(
-        to: [user.email_addresses.first.email],
-        subject: t('user_mailer.new_device_sign_in_before_2fa.subject', app_name: APP_NAME),
-      )
+    expect_delivered_email_count(1)
+    expect_delivered_email(
+      to: [user.email_addresses.first.email],
+      subject: t('user_mailer.new_device_sign_in_before_2fa.subject', app_name: APP_NAME),
+    )
 
-      fill_in_code_with_last_phone_otp
-      click_submit_default
+    fill_in_code_with_last_phone_otp
+    click_submit_default
 
-      expect_delivered_email_count(2)
-      expect_delivered_email(
-        to: [user.email_addresses.first.email],
-        subject: t('user_mailer.new_device_sign_in_after_2fa.subject', app_name: APP_NAME),
-      )
+    expect_delivered_email_count(2)
+    expect_delivered_email(
+      to: [user.email_addresses.first.email],
+      subject: t('user_mailer.new_device_sign_in_after_2fa.subject', app_name: APP_NAME),
+    )
 
-      disavow_last_action_and_reset_password
-    end
+    disavow_last_action_and_reset_password
+  end
 
-    context 'user with piv or cac' do
-      let(:user) { create(:user, :fully_registered, :with_piv_or_cac) }
+  context 'user with piv or cac' do
+    let(:user) { create(:user, :fully_registered, :with_piv_or_cac) }
 
-      scenario 'disavowing a sign-in after 2fa using piv or cac' do
-        signin_with_piv(user)
-        Capybara.reset_session!
+    scenario 'disavowing a sign-in after 2fa using piv or cac' do
+      signin_with_piv(user)
+      Capybara.reset_session!
 
-        disavow_last_action_and_reset_password
-      end
+      disavow_last_action_and_reset_password
     end
   end
 
@@ -84,22 +76,6 @@
     disavow_last_action_and_reset_password
   end
 
-  context 'when aggregated new device alerts is disabled' do
-    before do
-      allow(IdentityConfig.store).to receive(
-        :feature_new_device_alert_aggregation_enabled,
-      ).and_return(false)
-    end
-    scenario 'disavowing a new device sign in' do
-      allow(IdentityConfig.store).to receive(:otp_delivery_blocklist_maxretry).and_return(3)
-      signin(user.email, user.password)
-      Capybara.reset_session!
-      visit root_path
-      signin(user.email, user.password)
-      disavow_last_action_and_reset_password
-    end
-  end
-
   scenario 'disavowing a personal key sign in' do
     signin(user.email, user.password)
     choose_another_security_option(:personal_key)
diff --git a/spec/features/new_device_tracking_spec.rb b/spec/features/new_device_tracking_spec.rb
index 3b81e1f62a3..69a20e0cbb9 100644
--- a/spec/features/new_device_tracking_spec.rb
+++ b/spec/features/new_device_tracking_spec.rb
@@ -5,53 +5,8 @@
 
   let(:user) { create(:user, :fully_registered) }
 
-  context 'user has existing devices and aggregated new device alerts is disabled' do
+  context 'user has existing devices' do
     let(:user) { create(:user, :with_authenticated_device) }
-    before do
-      allow(IdentityConfig.store).to receive(
-        :feature_new_device_alert_aggregation_enabled,
-      ).and_return(false)
-    end
-
-    it 'sends a user notification on signin' do
-      sign_in_live_with_2fa(user)
-
-      expect(user.reload.devices.length).to eq 2
-
-      device = user.devices.order(created_at: :desc).first
-
-      expect_delivered_email_count(1)
-      expect_delivered_email(
-        to: [user.email_addresses.first.email],
-        subject: t('user_mailer.new_device_sign_in.subject', app_name: APP_NAME),
-        body: [device.last_used_at.in_time_zone('Eastern Time (US & Canada)').
-              strftime('%B %-d, %Y %H:%M Eastern Time'),
-               'From 127.0.0.1 (IP address potentially located in United States)'],
-      )
-    end
-
-    context 'from existing device' do
-      before do
-        Capybara.current_session.driver.browser.current_session.cookie_jar[:device] =
-          user.devices.first.cookie_uuid
-      end
-
-      it 'does not send a user notification on sign in' do
-        sign_in_live_with_2fa(user)
-
-        expect(user.reload.devices.length).to eq 1
-        expect_delivered_email_count(0)
-      end
-    end
-  end
-
-  context 'user has existing devices and aggregated new device alerts is enabled' do
-    let(:user) { create(:user, :with_authenticated_device) }
-    before do
-      allow(IdentityConfig.store).to receive(
-        :feature_new_device_alert_aggregation_enabled,
-      ).and_return(true)
-    end
 
     it 'sends a user notification on signin' do
       sign_in_live_with_2fa(user)
@@ -239,12 +194,10 @@
 
   context 'user does not have existing devices' do
     it 'should not send any notifications' do
-      allow(UserMailer).to receive(:new_device_sign_in).and_call_original
-
       sign_in_user(user)
 
       expect(user.devices.length).to eq 1
-      expect(UserMailer).not_to have_received(:new_device_sign_in)
+      expect_delivered_email_count(0)
     end
   end
 
diff --git a/spec/features/webauthn/hidden_spec.rb b/spec/features/webauthn/hidden_spec.rb
index 7b1f67bae47..1ad7393b430 100644
--- a/spec/features/webauthn/hidden_spec.rb
+++ b/spec/features/webauthn/hidden_spec.rb
@@ -96,7 +96,6 @@
           it 'redirects to options page on sign in and shows the option' do
             email ||= user.email_addresses.first.email
             password = user.password
-            allow(UserMailer).to receive(:new_device_sign_in).and_call_original
             visit new_user_session_path
             set_hidden_field('platform_authenticator_available', 'false')
             fill_in_credentials_and_submit(email, password)
diff --git a/spec/features/webauthn/sign_in_spec.rb b/spec/features/webauthn/sign_in_spec.rb
index 533c40d2062..5d1f8b0bd28 100644
--- a/spec/features/webauthn/sign_in_spec.rb
+++ b/spec/features/webauthn/sign_in_spec.rb
@@ -90,7 +90,6 @@
       before do
         email ||= user.email_addresses.first.email
         password = user.password
-        allow(UserMailer).to receive(:new_device_sign_in).and_call_original
         visit new_user_session_path
         set_hidden_field('platform_authenticator_available', 'false')
         fill_in_credentials_and_submit(email, password)
diff --git a/spec/mailers/previews/user_mailer_preview.rb b/spec/mailers/previews/user_mailer_preview.rb
index 90dbfaf556f..a421a980eb7 100644
--- a/spec/mailers/previews/user_mailer_preview.rb
+++ b/spec/mailers/previews/user_mailer_preview.rb
@@ -40,15 +40,6 @@ def personal_key_sign_in
       personal_key_sign_in(disavowal_token: SecureRandom.hex)
   end
 
-  def new_device_sign_in
-    UserMailer.with(user: user, email_address: email_address_record).new_device_sign_in(
-      date: 'February 25, 2019 15:02',
-      location: 'Washington, DC',
-      device_name: 'Chrome 123 on macOS',
-      disavowal_token: SecureRandom.hex,
-    )
-  end
-
   def new_device_sign_in_after_2fa
     UserMailer.with(user: user, email_address: email_address_record).new_device_sign_in_after_2fa(
       events: [
diff --git a/spec/mailers/user_mailer_spec.rb b/spec/mailers/user_mailer_spec.rb
index 9684a21a1fb..2584f10647e 100644
--- a/spec/mailers/user_mailer_spec.rb
+++ b/spec/mailers/user_mailer_spec.rb
@@ -160,50 +160,6 @@
     it_behaves_like 'an email that respects user email locale preference'
   end
 
-  describe '#new_device_sign_in' do
-    date = 'February 25, 2019 15:02'
-    location = 'Washington, DC'
-    device_name = 'Chrome ABC on macOS 123'
-    disavowal_token = 'asdf1234'
-    let(:mail) do
-      UserMailer.with(user: user, email_address: email_address).new_device_sign_in(
-        date: date,
-        location: location,
-        device_name: device_name,
-        disavowal_token: disavowal_token,
-      )
-    end
-
-    it_behaves_like 'a system email'
-
-    it 'sends to the current email' do
-      expect(mail.to).to eq [user.email]
-    end
-
-    it 'renders the subject' do
-      expect(mail.subject).to eq t('user_mailer.new_device_sign_in.subject', app_name: APP_NAME)
-    end
-
-    it 'renders the body' do
-      expect(mail.html_part.body).
-        to have_content(
-          strip_tags(
-            t(
-              'user_mailer.new_device_sign_in.info',
-              date: date,
-              location: location,
-              device_name: device_name,
-              app_name: APP_NAME,
-            ),
-          ),
-        )
-      expect(mail.html_part.body).to include(
-        '/events/disavow?disavowal_token=asdf1234',
-      )
-      expect_email_body_to_have_help_and_contact_links
-    end
-  end
-
   describe '#new_device_sign_in_before_2fa' do
     let(:event) { create(:event, event_type: :sign_in_before_2fa, user:, device: create(:device)) }
     subject(:mail) do
diff --git a/spec/services/user_alerts/alert_user_about_new_device_spec.rb b/spec/services/user_alerts/alert_user_about_new_device_spec.rb
index c69aa11899a..7c295e605f1 100644
--- a/spec/services/user_alerts/alert_user_about_new_device_spec.rb
+++ b/spec/services/user_alerts/alert_user_about_new_device_spec.rb
@@ -6,75 +6,13 @@
   let(:disavowal_token) { 'the_disavowal_token' }
   let(:device) { create(:device, user: user) }
 
-  describe '.call' do
-    context 'aggregated new device alerts enabled' do
-      before do
-        allow(IdentityConfig.store).to receive(
-          :feature_new_device_alert_aggregation_enabled,
-        ).and_return(true)
-      end
-
-      it 'does not send any emails' do
-        described_class.call(event:, device:, disavowal_token:)
-
-        expect_delivered_email_count(0)
-      end
-    end
-
-    context 'aggregated new device alerts disabled' do
-      before do
-        allow(IdentityConfig.store).to receive(
-          :feature_new_device_alert_aggregation_enabled,
-        ).and_return(false)
-      end
-
-      it 'sends an email to all confirmed email addresses' do
-        user.email_addresses.destroy_all
-        confirmed_email_addresses = create_list(:email_address, 2, user: user)
-        create(:email_address, user: user, confirmed_at: nil)
-
-        described_class.call(event:, device:, disavowal_token:)
-
-        expect_delivered_email_count(2)
-        expect_delivered_email(
-          to: [confirmed_email_addresses[0].email],
-          subject: t('user_mailer.new_device_sign_in.subject', app_name: APP_NAME),
-          body: [disavowal_token],
-        )
-        expect_delivered_email(
-          to: [confirmed_email_addresses[1].email],
-          subject: t('user_mailer.new_device_sign_in.subject', app_name: APP_NAME),
-          body: [disavowal_token],
-        )
-      end
-    end
-  end
-
   describe '.schedule_alert' do
     subject(:result) { described_class.schedule_alert(event:) }
 
-    context 'aggregated new device alerts enabled' do
-      before do
-        allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-          and_return(true)
-      end
-
-      it 'sets the user sign_in_new_device_at value to time of the given event' do
-        expect { result }.to change { user.reload.sign_in_new_device_at&.change(usec: 0) }.
-          from(nil).
-          to(event.created_at.change(usec: 0))
-      end
-    end
-
-    context 'aggregated new device alerts disabled' do
-      before do
-        allow(IdentityConfig.store).to receive(:feature_new_device_alert_aggregation_enabled).
-          and_return(false)
-      end
-
-      it 'does not set sign_in_new_device_at value' do
-        expect { result }.not_to change { user.reload.sign_in_new_device_at&.change(usec: 0) }
-      end
+    it 'sets the user sign_in_new_device_at value to time of the given event' do
+      expect { result }.to change { user.reload.sign_in_new_device_at&.change(usec: 0) }.
+        from(nil).
+        to(event.created_at.change(usec: 0))
     end
   end
 
diff --git a/spec/services/user_event_creator_spec.rb b/spec/services/user_event_creator_spec.rb
index 6f15de15628..30686caa949 100644
--- a/spec/services/user_event_creator_spec.rb
+++ b/spec/services/user_event_creator_spec.rb
@@ -61,20 +61,6 @@
         expect(event.device.last_ip).to eq(ip_address)
         expect(event.device.last_used_at).to be_within(1).of(Time.zone.now)
       end
-
-      it 'alerts the user if they have other devices' do
-        allow(UserAlerts::AlertUserAboutNewDevice).to receive(:call)
-        create(:device, user: user)
-
-        event, _disavowal_token = subject.create_user_event(event_type, user)
-
-        expect(event).to be_a(Event)
-        expect(UserAlerts::AlertUserAboutNewDevice).to have_received(:call).with(
-          event: user.events.first,
-          device: user.events.first.device,
-          disavowal_token: instance_of(String),
-        )
-      end
     end
 
     context 'when no device exists' do
@@ -106,20 +92,6 @@
             to(lambda { |value| value == Device.last.cookie_uuid })
         end
       end
-
-      it 'alerts the user if they have other devices' do
-        allow(UserAlerts::AlertUserAboutNewDevice).to receive(:call)
-        create(:device, user: user)
-
-        event, _disavowal_token = subject.create_user_event(event_type, user)
-
-        expect(event).to be_a(Event)
-        expect(UserAlerts::AlertUserAboutNewDevice).to have_received(:call).with(
-          event: user.events.first,
-          device: user.events.first.device,
-          disavowal_token: instance_of(String),
-        )
-      end
     end
   end
 
diff --git a/spec/support/features/session_helper.rb b/spec/support/features/session_helper.rb
index 8805558e97f..d2ffb80101a 100644
--- a/spec/support/features/session_helper.rb
+++ b/spec/support/features/session_helper.rb
@@ -49,7 +49,6 @@ def sign_up_and_2fa_ial1_user
     end
 
     def signin(email, password)
-      allow(UserMailer).to receive(:new_device_sign_in).and_call_original
       visit new_user_session_path
       set_hidden_field('platform_authenticator_available', 'true')
       fill_in_credentials_and_submit(email, password)
@@ -57,7 +56,6 @@ def signin(email, password)
     end
 
     def signin_with_piv(user = user_with_piv_cac)
-      allow(UserMailer).to receive(:new_device_sign_in).and_call_original
       visit new_user_session_path
       click_on t('account.login.piv_cac')
       fill_in_piv_cac_credentials_and_submit(user)
@@ -75,7 +73,6 @@ def signin_with_piv_error(error)
     end
 
     def signin_with_bad_piv
-      allow(UserMailer).to receive(:new_device_sign_in).and_call_original
       visit new_user_session_path
       click_on t('account.login.piv_cac')
       fill_in_bad_piv_cac_credentials_and_submit