diff --git a/db/migrate/create_outboxer_messages.rb b/db/migrate/create_outboxer_messages.rb
index 3ba45ab1..be4ad8ba 100644
--- a/db/migrate/create_outboxer_messages.rb
+++ b/db/migrate/create_outboxer_messages.rb
@@ -1,6 +1,8 @@
 class CreateOutboxerMessages < ActiveRecord::Migration[6.1]
   def up
     create_table :outboxer_messages do |t|
+      t.integer :lock_version, null: false, default: 0
+
       t.string :status, limit: 255, null: false
 
       t.string :messageable_id, limit: 255, null: false
diff --git a/lib/outboxer/message.rb b/lib/outboxer/message.rb
index 958b0aa7..601a8f83 100644
--- a/lib/outboxer/message.rb
+++ b/lib/outboxer/message.rb
@@ -119,10 +119,7 @@ def queue(messageable: nil, messageable_type: nil, messageable_id: nil,
 
         {
           id: message.id,
-          status: message.status,
-          messageable_type: message.messageable_type,
-          messageable_id: message.messageable_id,
-          updated_at: message.updated_at
+          lock_version: message.lock_version
         }
       end
     rescue MissingPartition
@@ -203,7 +200,9 @@ def publish(logger: nil, time: ::Time)
         begin
           yield message
         rescue StandardError => error
-          publishing_failed(id: message[:id], error: error, time: time)
+          publishing_failed(
+            id: message[:id], lock_version: message[:lock_version],
+            error: error, time: time)
 
           logger&.error(
             "Outboxer message publishing failed id=#{message[:id]} " \
@@ -211,7 +210,8 @@ def publish(logger: nil, time: ::Time)
               "#{error.class}: #{error.message}\n" \
               "#{error.backtrace.join("\n")}")
         rescue Exception => error
-          publishing_failed(id: message[:id], error: error, time: time)
+          publishing_failed(
+            id: message[:id], lock_version: message[:lock_version], error: error, time: time)
 
           logger&.fatal(
             "Outboxer message publishing failed id=#{message[:id]} " \
@@ -221,7 +221,7 @@ def publish(logger: nil, time: ::Time)
 
           raise
         else
-          published(id: message[:id], time: time)
+          published(id: message[:id], lock_version: message[:lock_version], time: time)
 
           logger&.info(
             "Outboxer message published id=#{message[:id]} " \
@@ -254,7 +254,7 @@ def publishing(time: ::Time)
       ActiveRecord::Base.connection_pool.with_connection do
         ActiveRecord::Base.transaction do
           message = Models::Message
-            .select(:id, :messageable_type, :messageable_id)
+            .select(:id, :lock_version, :messageable_type, :messageable_id)
             .where(status: Status::QUEUED)
             .order(:id)
             .limit(1)
@@ -265,6 +265,7 @@ def publishing(time: ::Time)
             nil
           else
             message.update!(
+              lock_version: message.lock_version,
               status: Status::PUBLISHING,
               updated_at: current_utc_time,
               publishing_at: current_utc_time)
@@ -284,9 +285,10 @@ def publishing(time: ::Time)
               .update_all(["value = value + ?, updated_at = ?", 1, current_utc_time])
 
             {
-              id: message[:id],
-              messageable_type: message[:messageable_type],
-              messageable_id: message[:messageable_id]
+              id: message.id,
+              lock_version: message.lock_version,
+              messageable_type: message.messageable_type,
+              messageable_id: message.messageable_id
             }
           end
         end
@@ -306,7 +308,7 @@ def publishing(time: ::Time)
     # @note Executes within a transaction using a `SELECT ... FOR UPDATE` lock.
     # @example
     #   Outboxer::Message.published(id: message[:id], time: Time)
-    def published(id:, time: ::Time)
+    def published(id:, lock_version:, time: ::Time)
       current_utc_time = time.now.utc
 
       ActiveRecord::Base.connection_pool.with_connection do
@@ -317,6 +319,8 @@ def published(id:, time: ::Time)
             raise Error, "Status must be publishing"
           end
 
+          message.update!(lock_version: lock_version, updated_at: Time.now.utc)
+
           message.exceptions.each { |exception| exception.frames.each(&:delete) }
           message.exceptions.delete_all
           message.delete
@@ -335,7 +339,7 @@ def published(id:, time: ::Time)
             .where(status: Status::PUBLISHED, partition: partition)
             .update_all(["value = value + ?, updated_at = ?", 1, current_utc_time])
 
-          nil
+          {}
         end
       end
     end
@@ -354,7 +358,7 @@ def published(id:, time: ::Time)
     # @note Runs inside a transaction and uses `SELECT ... FOR UPDATE` locking.
     # @example
     #   Outboxer::Message.publishing_failed(id: message[:id], time: Time)
-    def publishing_failed(id:, error: nil, time: ::Time)
+    def publishing_failed(id:, lock_version:, error: nil, time: ::Time)
       current_utc_time = time.now.utc
 
       ActiveRecord::Base.connection_pool.with_connection do
@@ -366,6 +370,7 @@ def publishing_failed(id:, error: nil, time: ::Time)
           end
 
           message.update!(
+            lock_version: lock_version,
             status: Status::FAILED,
             updated_at: current_utc_time, failed_at: current_utc_time)
 
@@ -392,7 +397,9 @@ def publishing_failed(id:, error: nil, time: ::Time)
             .where(status: Status::FAILED, partition: partition)
             .update_all(["value = value + ?, updated_at = ?", 1, current_utc_time])
 
-          nil
+          {
+            lock_version: message.lock_version
+          }
         end
       end
     end
@@ -400,6 +407,7 @@ def publishing_failed(id:, error: nil, time: ::Time)
     # Serializes message attributes into a hash.
     #
     # @param id [Integer] message ID.
+    # @param lock_version [Integer] message lock_version.
     # @param status [String] message status.
     # @param messageable_type [String] type of the messageable entity.
     # @param messageable_id [String] ID of the messageable entity.
@@ -411,11 +419,12 @@ def publishing_failed(id:, error: nil, time: ::Time)
     # @param publisher_id [Integer, nil] optional publisher ID.
     # @param publisher_name [String, nil] optional publisher name.
     # @return [Hash] serialized message details.
-    def serialize(id:, status:, messageable_type:, messageable_id:, updated_at:,
+    def serialize(id:, lock_version:, status:, messageable_type:, messageable_id:, updated_at:,
                   queued_at: nil, publishing_at: nil, published_at: nil, failed_at: nil,
                   publisher_id: nil, publisher_name: nil)
       {
         id: id,
+        lock_version: lock_version,
         status: status,
         messageable_type: messageable_type,
         messageable_id: messageable_id,
@@ -445,6 +454,7 @@ def find_by_id(id:)
 
           {
             id: message.id,
+            lock_version: message.lock_version,
             status: message.status,
             messageable_type: message.messageable_type,
             messageable_id: message.messageable_id,
@@ -479,12 +489,13 @@ def find_by_id(id:)
     # Deletes a message by ID.
     # @param id [Integer] the ID of the message to delete.
     # @return [Hash] details of the deleted message.
-    def delete(id:, time: ::Time)
+    def delete(id:, lock_version:, time: ::Time)
       current_utc_time = time.now.utc
 
       ActiveRecord::Base.connection_pool.with_connection do
         ActiveRecord::Base.transaction do
           message = Models::Message.includes(exceptions: :frames).lock.find_by!(id: id)
+          message.update!(lock_version: lock_version, updated_at: current_utc_time)
 
           message.exceptions.each { |exception| exception.frames.each(&:delete) }
           message.exceptions.delete_all
@@ -516,7 +527,7 @@ def can_requeue?(status:)
     # @param publisher_name [String, nil] the name of the publisher.
     # @param time [Time] current time context used to update timestamps.
     # @return [Hash] updated message details.
-    def requeue(id:, publisher_id: nil, publisher_name: nil,
+    def requeue(id:, lock_version:, publisher_id: nil, publisher_name: nil,
                 time: ::Time)
       current_utc_time = time.now.utc
 
@@ -526,11 +537,10 @@ def requeue(id:, publisher_id: nil, publisher_name: nil,
 
           partition = calculate_partition(id: message.id)
 
-          Models::MessageCount
-            .where(status: message.status, partition: partition)
-            .update_all(["value = value - ?, updated_at = ?", 1, current_utc_time])
+          original_status = message.status
 
           message.update!(
+            lock_version: lock_version,
             status: Message::Status::QUEUED,
             updated_at: current_utc_time,
             queued_at: current_utc_time,
@@ -541,11 +551,15 @@ def requeue(id:, publisher_id: nil, publisher_name: nil,
             publisher_name: publisher_name)
 
           Models::MessageCount
-            .where(status: Status::QUEUED, partition: partition)
+            .where(status: original_status, partition: partition)
+            .update_all(["value = value - ?, updated_at = ?", 1, current_utc_time])
+
+          Models::MessageCount
+            .where(status: message.status, partition: partition)
             .update_all(["value = value + ?, updated_at = ?", 1, current_utc_time])
 
           Models::MessageTotal
-            .where(status: Status::QUEUED, partition: partition)
+            .where(status: message.status, partition: partition)
             .update_all(["value = value + ?, updated_at = ?", 1, current_utc_time])
 
           { id: id }
@@ -631,6 +645,7 @@ def list(status: LIST_STATUS_DEFAULT,
         messages: paginated_messages.map do |message|
           {
             id: message.id,
+            lock_version: message.lock_version,
             status: message.status.to_sym,
             messageable_type: message.messageable_type,
             messageable_id: message.messageable_id,
diff --git a/lib/outboxer/web.rb b/lib/outboxer/web.rb
index c0394447..005edd67 100755
--- a/lib/outboxer/web.rb
+++ b/lib/outboxer/web.rb
@@ -494,56 +494,68 @@ def normalise_query_string(status: Message::LIST_STATUS_DEFAULT,
     end
 
     post "/messages/update" do
-      ids = params[:selected_ids].map(&:to_i)
       flash = {}
 
+      selected_messages = params.fetch("selected_messages", []).map do |pair|
+        id, lock_version = pair.split(":").map(&:to_i)
+        { id: id, lock_version: lock_version }
+      end
+
       case params[:action]
       when "requeue_by_ids"
-        requeued_count = 0
-        failed_count = 0
+        requeued_message_count = 0
+        failed_message_count = 0
 
-        ids.each do |id|
-          Outboxer::Message.requeue(id: id)
-          requeued_count += 1
+        selected_messages.each do |selected_message|
+          Outboxer::Message.requeue(
+            id: selected_message[:id],
+            lock_version: selected_message[:lock_version]
+          )
+          requeued_message_count += 1
         rescue StandardError => error
           settings.logger.error(
-            "[Outboxer::Web] Failed to requeue message id=#{id}\n" \
+            "[Outboxer::Web] Failed to requeue message id=#{selected_message[:id]}\n" \
             "error_class=#{error.class}\n" \
             "error_message=#{error.message.inspect}"
           )
-          failed_count += 1
+          failed_message_count += 1
         end
 
-        if requeued_count.positive?
-          flash[:success] = "Requeued #{pluralise(requeued_count, "message")}"
+        if requeued_message_count.positive?
+          flash[:success] = "Requeued #{pluralise(requeued_message_count, "message")}"
         end
 
-        if failed_count.positive?
-          flash[:danger] = "Requeue failed for #{pluralise(failed_count, "message")}"
+        if failed_message_count.positive?
+          flash[:danger] = "Requeue failed for #{pluralise(failed_message_count, "message")}"
         end
+
       when "delete_by_ids"
-        deleted_count = 0
-        failed_count = 0
+        deleted_message_count = 0
+        failed_message_count = 0
 
-        ids.each do |id|
-          Outboxer::Message.delete(id: id)
-          deleted_count += 1
+        selected_messages.each do |selected_message|
+          Outboxer::Message.delete(
+            id: selected_message[:id],
+            lock_version: selected_message[:lock_version]
+          )
+          deleted_message_count += 1
         rescue StandardError => error
           settings.logger.error(
-            "[Outboxer::Web] Failed to delete message id=#{id}\n" \
+            "[Outboxer::Web] Failed to delete message id=#{selected_message[:id]}\n" \
             "error_class=#{error.class}\n" \
             "error_message=#{error.message.inspect}"
           )
-          failed_count += 1
+          failed_message_count += 1
         end
 
-        if deleted_count.positive?
-          flash[:success] = "Deleted #{pluralise(deleted_count, "message")}"
+        if deleted_message_count.positive?
+          flash[:success] = "Deleted #{pluralise(deleted_message_count, "message")}"
         end
 
-        if failed_count.positive?
-          flash[:danger] = "Delete failed for #{pluralise(failed_count, "message")}"
+        if failed_message_count.positive?
+          flash[:danger] = "Delete failed for #{pluralise(failed_message_count, "message")}"
         end
+
       else
         raise "Unknown action: #{params[:action]}"
       end
@@ -656,7 +668,7 @@ def normalise_query_string(status: Message::LIST_STATUS_DEFAULT,
     end
 
     post "/message/:id/requeue" do
-      Message.requeue(id: params[:id])
+      Message.requeue(id: params[:id], lock_version: params[:lock_version])
 
       denormalised_query_params = denormalise_query_params(
         status: params[:status],
@@ -679,7 +691,7 @@ def normalise_query_string(status: Message::LIST_STATUS_DEFAULT,
     end
 
     post "/message/:id/delete" do
-      Message.delete(id: params[:id])
+      Message.delete(id: params[:id], lock_version: params[:lock_version])
 
       denormalised_query_params = denormalise_query_params(
         status: params[:status],
diff --git a/lib/outboxer/web/views/message.erb b/lib/outboxer/web/views/message.erb
index 055d3c1d..119bf69a 100644
--- a/lib/outboxer/web/views/message.erb
+++ b/lib/outboxer/web/views/message.erb
@@ -4,25 +4,33 @@
             <h3 class="mb-0">Message <%= message[:id] %></h3>
             <div class="card-header-buttons">
                 <!-- Requeue Form -->
-                <form action="<%= outboxer_path("/message/#{message[:id]}/requeue") %>" method="post" style="display: inline;">
-                    <% normalised_query_params.each do |key, param| %>
-                        <input type="hidden" name="<%= key %>" value="<%= param %>">
-                    <% end %>
-                    <button type="submit" class="btn btn-sm btn-outline-secondary me-2" aria-label="Requeue"
-                        <%= 'disabled' unless Outboxer::Message.can_requeue?(status: message[:status]) %>>
-                        <i class="bi bi-arrow-clockwise"></i> Requeue
-                    </button>
+                <form action="<%= outboxer_path("/message/#{message[:id]}/requeue") %>" method="post"
+                    style="display: inline;">
+                <% normalised_query_params.each do |key, param| %>
+                    <input type="hidden" name="<%= key %>" value="<%= param %>">
+                <% end %>
+                <input type="hidden" name="lock_version" value="<%= message[:lock_version] %>">
+
+                <button type="submit" class="btn btn-sm btn-outline-secondary me-2"
+                        aria-label="Requeue"
+                        <%= 'disabled' unless Outboxer::Message
+                                .can_requeue?(status: message[:status]) %>>
+                    <i class="bi bi-arrow-clockwise"></i> Requeue
+                </button>
                 </form>
+
                 <!-- Delete Form -->
-                <form action="<%= outboxer_path("/message/#{message[:id]}/delete") %>" method="post" style="display: inline;"
+                <form action="<%= outboxer_path("/message/#{message[:id]}/delete") %>" method="post"
+                    style="display: inline;"
                     onsubmit="return confirm('Are you sure you want to delete this message?');">
+                <% normalised_query_params.each do |key, param| %>
+                    <input type="hidden" name="<%= key %>" value="<%= param %>">
+                <% end %>
+                <input type="hidden" name="lock_version" value="<%= message[:lock_version] %>">
 
-                    <% normalised_query_params.each do |key, param| %>
-                        <input type="hidden" name="<%= key %>" value="<%= param %>">
-                    <% end %>
-                    <button type="submit" class="btn btn-sm btn-outline-danger" aria-label="Delete">
-                        <i class="bi bi-trash"></i> Delete
-                    </button>
+                <button type="submit" class="btn btn-sm btn-outline-danger" aria-label="Delete">
+                    <i class="bi bi-trash"></i> Delete
+                </button>
                 </form>
             </div>
         </div>
diff --git a/lib/outboxer/web/views/messages.erb b/lib/outboxer/web/views/messages.erb
index 88cb3060..32581d73 100644
--- a/lib/outboxer/web/views/messages.erb
+++ b/lib/outboxer/web/views/messages.erb
@@ -14,11 +14,12 @@
                     <!-- Requeue Page -->
                     <form action="<%= outboxer_path("/messages/update") %>" method="post" class="me-2">
                         <% normalised_query_params.each do |key, param| %>
-                        <input type="hidden" name="<%= key %>" value="<%= param %>">
+                            <input type="hidden" name="<%= key %>" value="<%= param %>">
                         <% end %>
                         <input type="hidden" name="action" value="requeue_by_ids">
-                        <% messages.each do |message| %>
-                        <input type="hidden" name="selected_ids[]" value="<%= message[:id] %>">
+                        <% messages.each_with_index do |message, i| %>
+                            <input type="hidden" name="selected_messages[]"
+                                   value="<%= "#{message[:id]}:#{message[:lock_version]}" %>">
                         <% end %>
                         <button type="submit" class="btn btn-sm btn-outline-secondary"
                         <%= 'disabled' unless Outboxer::Message.can_requeue?(status: denormalised_query_params[:status]) %>>
@@ -32,14 +33,16 @@
                             <input type="hidden" name="<%= key %>" value="<%= param %>">
                         <% end %>
                         <input type="hidden" name="action" value="delete_by_ids">
-                        <% messages.each do |message| %>
-                            <input type="hidden" name="selected_ids[]" value="<%= message[:id] %>">
+                        <% messages.each_with_index do |message, i| %>
+                            <input type="hidden" name="selected_messages[]"
+                                   value="<%= "#{message[:id]}:#{message[:lock_version]}" %>">
                         <% end %>
                         <button type="submit" class="btn btn-sm btn-outline-danger">
-                            <i class="bi bi-trash"></i> Delete Page
+                        <i class="bi bi-trash"></i> Delete Page
                         </button>
                     </form>
                     </div>
+
                     <!-- Buttons aligned underneath the header on the smallest screens -->
                     <div class="col-12 d-sm-none mt-2">
                     <% if Outboxer::Message.can_requeue?(status: denormalised_query_params[:status]) %>
@@ -48,8 +51,9 @@
                             <input type="hidden" name="<%= key %>" value="<%= param %>">
                         <% end %>
                         <input type="hidden" name="action" value="requeue_by_ids">
-                        <% messages.each do |message| %>
-                            <input type="hidden" name="selected_ids[]" value="<%= message[:id] %>">
+                        <% messages.each_with_index do |message, i| %>
+                            <input type="hidden" name="selected_messages[]"
+                                   value="<%= "#{message[:id]}:#{message[:lock_version]}" %>">
                         <% end %>
                         <button type="submit" class="btn btn-sm btn-outline-secondary w-100">
                             <i class="bi bi-arrow-clockwise"></i> Requeue Page
@@ -59,14 +63,15 @@
 
                     <form action="<%= outboxer_path("/messages/update") %>" method="post">
                         <% normalised_query_params.each do |key, param| %>
-                            <input type="hidden" name="<%= key %>" value="<%= param %>">
+                        <input type="hidden" name="<%= key %>" value="<%= param %>">
                         <% end %>
                         <input type="hidden" name="action" value="delete_by_ids">
-                        <% messages.each do |message| %>
-                            <input type="hidden" name="selected_ids[]" value="<%= message[:id] %>">
+                        <% messages.each_with_index do |message, i| %>
+                            <input type="hidden" name="selected_messages[]"
+                                   value="<%= "#{message[:id]}:#{message[:lock_version]}" %>">
                         <% end %>
                         <button type="submit" class="btn btn-sm btn-outline-danger w-100">
-                            <i class="bi bi-trash"></i> Delete Page
+                        <i class="bi bi-trash"></i> Delete Page
                         </button>
                     </form>
                     </div>
@@ -75,29 +80,29 @@
         </div>
         <!-- Bulk Actions Form -->
         <form id="bulkActionForm" action="<%= outboxer_path("/messages/update") %>" method="post">
-            <div class="card-toolbar py-2 d-none" id="bulkActionsToolbar" style="border-top: 1px solid #eee; border-bottom: 1px solid #eee; background-color: #E9F5FB;">
-                <div class="container">
-                    <div class="row justify-content-start">
-                        <div class="col-auto">
-                            <% normalised_query_params.each do |key, param| %>
-                                <input type="hidden" name="<%= key %>" value="<%= param %>">
-                            <% end %>
+        <div class="card-toolbar py-2" id="bulkActionsToolbar"
+            style="border-top:1px solid #eee;border-bottom:1px solid #eee;background-color:#E9F5FB;">
+            <div class="container">
+            <div class="row justify-content-start">
+                <div class="col-auto">
+                <% normalised_query_params.each do |key, param| %>
+                    <input type="hidden" name="<%= key %>" value="<%= param %>">
+                <% end %>
 
-                            <!-- Requeue Selected Button -->
-                            <button class="btn btn-sm btn-outline-secondary me-2" type="submit" name="action"
-                                    value="requeue_by_ids" data-bs-toggle="tooltip" data-bs-placement="top"
-                                    title="Requeue selected" <%= 'disabled' unless Outboxer::Message.can_requeue?(status: denormalised_query_params[:status]) %>>
-                                <i class="bi bi-arrow-clockwise"></i> Requeue Selected
-                            </button>
+                <button class="btn btn-sm btn-outline-secondary me-2" type="submit"
+                        name="action" value="requeue_by_ids"
+                        <%= 'disabled' unless Outboxer::Message.can_requeue?(status: denormalised_query_params[:status]) %>>
+                    <i class="bi bi-arrow-clockwise"></i> Requeue Selected
+                </button>
 
-                            <!-- Delete Selected Button -->
-                            <button class="btn btn-sm btn-outline-danger" type="submit" name="action" value="delete_by_ids" data-bs-toggle="tooltip" data-bs-placement="top" title="Delete selected">
-                                <i class="bi bi-trash"></i> Delete Selected
-                            </button>
-                        </div>
-                    </div>
+                <button class="btn btn-sm btn-outline-danger" type="submit"
+                        name="action" value="delete_by_ids">
+                    <i class="bi bi-trash"></i> Delete Selected
+                </button>
                 </div>
             </div>
+            </div>
+        </div>
         </form>
         <div class="card-body">
             <% if messages.empty? %>
@@ -126,7 +131,13 @@
                         <tbody>
                             <% messages.each do |message| %>
                                 <tr>
-                                    <td><input type="checkbox" class="individual-check" form="bulkActionForm" name="selected_ids[]" value="<%= message[:id] %>"></td>
+                                    <td>
+                                        <input type="checkbox" class="individual-check" form="bulkActionForm"
+                                               data-message-id="<%= message[:id] %>"
+                                               data-lock-version="<%= message[:lock_version] %>"
+                                               name="selected_messages[]"
+                                               value="<%= "#{message[:id]}:#{message[:lock_version]}" %>">
+                                    </td>
                                     <td scope="row">
                                         <a href="<%= outboxer_path("/message/#{message[:id]}#{normalised_query_string}") %>" class="custom-link">
                                             <%= message[:id] %>
@@ -160,23 +171,28 @@
                                         <!-- Requeue Button Form -->
                                         <form action="<%= outboxer_path("/message/#{message[:id]}/requeue") %>" method="post">
                                             <% normalised_query_params.each do |key, param| %>
-                                                <input type="hidden" name="<%= key %>" value="<%= param %>">
+                                            <input type="hidden" name="<%= key %>" value="<%= param %>">
                                             <% end %>
-                                            <button type="submit" class="btn btn-sm btn-outline-secondary me-1 d-flex align-items-center
-                                                            justify-content-center" <%= 'disabled' unless Outboxer::Message
-                                                                                    .can_requeue?(status: denormalised_query_params[:status]) %>>
-                                                <i class="bi bi-arrow-clockwise me-1"></i>
-                                                <span>Requeue</span>
+                                            <input type="hidden" name="lock_version" value="<%= message[:lock_version] %>">
+
+                                            <button type="submit"
+                                                    class="btn btn-sm btn-outline-secondary me-1 d-flex align-items-center justify-content-center"
+                                                    <%= 'disabled' unless Outboxer::Message
+                                                        .can_requeue?(status: denormalised_query_params[:status]) %>>
+                                            <i class="bi bi-arrow-clockwise me-1"></i>
+                                            <span>Requeue</span>
                                             </button>
                                         </form>
 
                                         <!-- Delete Button Form -->
                                         <form action="<%= outboxer_path("/message/#{message[:id]}/delete") %>" method="post">
                                             <% normalised_query_params.each do |key, param| %>
-                                                <input type="hidden" name="<%= key %>" value="<%= param %>">
+                                            <input type="hidden" name="<%= key %>" value="<%= param %>">
                                             <% end %>
+                                            <input type="hidden" name="lock_version" value="<%= message[:lock_version] %>">
 
-                                            <button type="submit" class="btn btn-sm btn-outline-danger ms-1 d-flex align-items-center justify-content-center">
+                                            <button type="submit"
+                                                    class="btn btn-sm btn-outline-danger ms-1 d-flex align-items-center justify-content-center">
                                             <i class="bi bi-trash me-1"></i>
                                             <span>Delete</span>
                                             </button>
@@ -242,58 +258,48 @@
     </div>
 </div>
 <script>
-    document.addEventListener('DOMContentLoaded', function () {
-        const checkboxes = document.querySelectorAll('.individual-check');
-        const checkAll = document.getElementById('checkAll');
-        const bulkActionsToolbar = document.getElementById('bulkActionsToolbar');
+document.addEventListener('DOMContentLoaded', function () {
+  const checkboxes = document.querySelectorAll('.individual-check');
+  const checkAll = document.getElementById('checkAll');
+  const bulkActionsToolbar = document.getElementById('bulkActionsToolbar');
 
-        function toggleBulkActionsToolbar() {
-            const anyChecked = Array.from(checkboxes).some(checkbox => checkbox.checked);
-            bulkActionsToolbar.classList.toggle('d-none', !anyChecked);
-        }
+  // Hide toolbar initially (enhancement only)
+  bulkActionsToolbar.classList.add('d-none');
 
-        checkboxes.forEach(checkbox => {
-            checkbox.addEventListener('change', toggleBulkActionsToolbar);
-        });
+  function toggleBulkActionsToolbar() {
+    const anyChecked = Array.from(checkboxes).some(checkbox => checkbox.checked);
+    bulkActionsToolbar.classList.toggle('d-none', !anyChecked);
+  }
 
+  // Individual checkbox toggles toolbar visibility
+  checkboxes.forEach(checkbox => {
+    checkbox.addEventListener('change', toggleBulkActionsToolbar);
+  });
 
-        if (checkAll) {
-            checkAllElement.addEventListener('change', function (e) {
-                var checkboxes = document.querySelectorAll('.individual-check');
-                for (var i = 0; i < checkboxes.length; i++) {
-                    checkboxes[i].checked = e.target.checked;
-                }
-            });
-
-            checkAll.addEventListener('change', function () {
-                toggleBulkActionsToolbar();
-            });
-        }
-
-        const deleteAllBtn = document.getElementById('deleteAllBtn');
-
-        if (deleteAllBtn) {
-            deleteAllBtn.addEventListener('click', function(e) {
-                const confirmation = confirm('Are you sure you want to delete all?');
-                if (!confirmation) {
-                    e.preventDefault();
-                    return false;
-                }
-            });
-        }
+  // "Select All" toggle
+  if (checkAll) {
+    checkAll.addEventListener('change', function (e) {
+      checkboxes.forEach(box => (box.checked = e.target.checked));
+      toggleBulkActionsToolbar();
+    });
+  }
 
-        const retryAllBtn = document.getElementById('retryAllBtn');
+  // Confirmation prompts for destructive actions
+  const deleteAllBtn = document.getElementById('deleteAllBtn');
+  if (deleteAllBtn) {
+    deleteAllBtn.addEventListener('click', function (e) {
+      if (!confirm('Are you sure you want to delete all?')) e.preventDefault();
+    });
+  }
 
-        if (retryAllBtn) {
-            retryAllBtn.addEventListener('click', function(e) {
-                const confirmation = confirm('Are you sure you want to retry all?');
-                if (!confirmation) {
-                    e.preventDefault();
-                    return false;
-                }
-            });
-        }
+  const retryAllBtn = document.getElementById('retryAllBtn');
+  if (retryAllBtn) {
+    retryAllBtn.addEventListener('click', function (e) {
+      if (!confirm('Are you sure you want to retry all?')) e.preventDefault();
     });
+  }
 
-    var checkAllElement = document.getElementById('checkAll');
+  // Initial state
+  toggleBulkActionsToolbar();
+});
 </script>
diff --git a/spec/lib/outboxer/message/delete_spec.rb b/spec/lib/outboxer/message/delete_spec.rb
index 7b3938eb..bf3613a1 100644
--- a/spec/lib/outboxer/message/delete_spec.rb
+++ b/spec/lib/outboxer/message/delete_spec.rb
@@ -13,7 +13,7 @@ module Outboxer
         let!(:exception) { create(:outboxer_exception, message: message) }
         let!(:frame) { create(:outboxer_frame, exception: exception) }
 
-        let!(:result) { Message.delete(id: message.id) }
+        let!(:result) { Message.delete(id: message.id, lock_version: message.lock_version) }
 
         it "deletes the message" do
           expect(Models::Message).not_to exist(message.id)
@@ -42,7 +42,7 @@ module Outboxer
         let!(:exception) { create(:outboxer_exception, message: message) }
         let!(:frame) { create(:outboxer_frame, exception: exception) }
 
-        let!(:result) { Message.delete(id: message.id) }
+        let!(:result) { Message.delete(id: message.id, lock_version: message.lock_version) }
 
         it "deletes the message" do
           expect(Models::Message).not_to exist(message.id)
diff --git a/spec/lib/outboxer/message/list/filter_spec.rb b/spec/lib/outboxer/message/list/filter_spec.rb
index 2debbdca..79008b6a 100644
--- a/spec/lib/outboxer/message/list/filter_spec.rb
+++ b/spec/lib/outboxer/message/list/filter_spec.rb
@@ -51,6 +51,7 @@ module Outboxer
             messages: [
               {
                 id: message_1.id,
+                lock_version: message_1.lock_version,
                 status: message_1.status.to_sym,
                 messageable_type: message_1.messageable_type,
                 messageable_id: message_1.messageable_id,
@@ -65,6 +66,7 @@ module Outboxer
               },
               {
                 id: message_4.id,
+                lock_version: message_4.lock_version,
                 status: message_4.status.to_sym,
                 messageable_type: message_4.messageable_type,
                 messageable_id: message_4.messageable_id,
@@ -89,6 +91,7 @@ module Outboxer
             messages: [
               {
                 id: message_5.id,
+                lock_version: message_5.lock_version,
                 status: message_5.status.to_sym,
                 messageable_type: message_5.messageable_type,
                 messageable_id: message_5.messageable_id,
@@ -113,6 +116,7 @@ module Outboxer
             messages: [
               {
                 id: message_2.id,
+                lock_version: message_2.lock_version,
                 status: message_2.status.to_sym,
                 messageable_type: message_2.messageable_type,
                 messageable_id: message_2.messageable_id,
diff --git a/spec/lib/outboxer/message/list/no_arguments_spec.rb b/spec/lib/outboxer/message/list/no_arguments_spec.rb
index 7dd90b61..4ba176b3 100644
--- a/spec/lib/outboxer/message/list/no_arguments_spec.rb
+++ b/spec/lib/outboxer/message/list/no_arguments_spec.rb
@@ -61,6 +61,7 @@ module Outboxer
             messages: [
               {
                 id: message_1.id,
+                lock_version: message_1.lock_version,
                 status: message_1.status.to_sym,
                 messageable_type: message_1.messageable_type,
                 messageable_id: message_1.messageable_id,
@@ -75,6 +76,7 @@ module Outboxer
               },
               {
                 id: message_2.id,
+                lock_version: message_2.lock_version,
                 status: message_2.status.to_sym,
                 messageable_type: message_2.messageable_type,
                 messageable_id: message_2.messageable_id,
@@ -89,6 +91,7 @@ module Outboxer
               },
               {
                 id: message_3.id,
+                lock_version: message_3.lock_version,
                 status: message_3.status.to_sym,
                 messageable_type: message_3.messageable_type,
                 messageable_id: message_3.messageable_id,
@@ -103,6 +106,7 @@ module Outboxer
               },
               {
                 id: message_4.id,
+                lock_version: message_4.lock_version,
                 status: message_4.status.to_sym,
                 messageable_type: message_4.messageable_type,
                 messageable_id: message_4.messageable_id,
@@ -117,6 +121,7 @@ module Outboxer
               },
               {
                 id: message_5.id,
+                lock_version: message_5.lock_version,
                 status: message_5.status.to_sym,
                 messageable_type: message_5.messageable_type,
                 messageable_id: message_5.messageable_id,
diff --git a/spec/lib/outboxer/message/publish_spec.rb b/spec/lib/outboxer/message/publish_spec.rb
index 66074ef3..0c45b6d6 100644
--- a/spec/lib/outboxer/message/publish_spec.rb
+++ b/spec/lib/outboxer/message/publish_spec.rb
@@ -23,11 +23,10 @@ module Outboxer
             end
 
             expect(yielded_id).to eq(queued_message.id)
-            expect(result).to eq({
+            expect(result).to include(
               id: queued_message.id,
               messageable_type: queued_message.messageable_type,
-              messageable_id: queued_message.messageable_id
-            })
+              messageable_id: queued_message.messageable_id)
 
             expect(Models::Message.published.count).to eql(0)
           end
@@ -37,7 +36,7 @@ module Outboxer
               raise StandardError, "temporary failure"
             end
 
-            expect(result).to eq({
+            expect(result).to include({
               id: queued_message.id,
               messageable_type: queued_message.messageable_type,
               messageable_id: queued_message.messageable_id
diff --git a/spec/lib/outboxer/message/requeue_spec.rb b/spec/lib/outboxer/message/requeue_spec.rb
index 29bb4d8c..9cea628c 100644
--- a/spec/lib/outboxer/message/requeue_spec.rb
+++ b/spec/lib/outboxer/message/requeue_spec.rb
@@ -6,7 +6,9 @@ module Outboxer
       context "when failed message" do
         let!(:failed_message) { create(:outboxer_message, :failed) }
 
-        let!(:queued_message) { Message.requeue(id: failed_message.id) }
+        let!(:queued_message) do
+          Message.requeue(id: failed_message.id, lock_version: failed_message.lock_version)
+        end
 
         it "returns queued message" do
           expect(queued_message[:id]).to eq(failed_message.id)
@@ -24,7 +26,7 @@ module Outboxer
         let!(:updated_at) { queued_message.updated_at }
 
         it "modifies updated_at" do
-          Message.requeue(id: queued_message.id)
+          Message.requeue(id: queued_message.id, lock_version: queued_message.lock_version)
 
           queued_message.reload
 
diff --git a/spec/lib/outboxer/message/serialize_spec.rb b/spec/lib/outboxer/message/serialize_spec.rb
index 3777c5d5..14da995d 100644
--- a/spec/lib/outboxer/message/serialize_spec.rb
+++ b/spec/lib/outboxer/message/serialize_spec.rb
@@ -7,6 +7,7 @@ module Outboxer
         expect(
           Message.serialize(
             id: 1,
+            lock_version: 2,
             status: "publishing",
             messageable_type: "Invoice",
             messageable_id: "INV-001",
@@ -20,6 +21,7 @@ module Outboxer
         ).to eq(
           {
             id: 1,
+            lock_version: 2,
             status: "publishing",
             messageable_type: "Invoice",
             messageable_id: "INV-001",
diff --git a/spec/lib/outboxer/web/message/delete_spec.rb b/spec/lib/outboxer/web/message/delete_spec.rb
index cd4951cc..0ebf7a23 100644
--- a/spec/lib/outboxer/web/message/delete_spec.rb
+++ b/spec/lib/outboxer/web/message/delete_spec.rb
@@ -15,7 +15,7 @@ def app
   before do
     header "Host", "localhost"
 
-    post "/message/#{message[:id]}/delete"
+    post "/message/#{message[:id]}/delete", { lock_version: message[:lock_version] }
 
     follow_redirect!
   end
diff --git a/spec/lib/outboxer/web/message/requeue_spec.rb b/spec/lib/outboxer/web/message/requeue_spec.rb
index dd51c574..3d932d1c 100644
--- a/spec/lib/outboxer/web/message/requeue_spec.rb
+++ b/spec/lib/outboxer/web/message/requeue_spec.rb
@@ -15,7 +15,7 @@ def app
   before do
     header "Host", "localhost"
 
-    post "/message/#{message[:id]}/requeue"
+    post "/message/#{message[:id]}/requeue", { lock_version: message[:lock_version] }
 
     follow_redirect!
   end
diff --git a/spec/lib/outboxer/web/messages/update_spec.rb b/spec/lib/outboxer/web/messages/update_spec.rb
index 715bc669..af5c305c 100644
--- a/spec/lib/outboxer/web/messages/update_spec.rb
+++ b/spec/lib/outboxer/web/messages/update_spec.rb
@@ -1,5 +1,4 @@
 require "rails_helper"
-
 require_relative "../../../../../lib/outboxer/web"
 
 RSpec.describe "POST /messages/update", type: :request do
@@ -24,16 +23,16 @@ def app
   before do
     message_2.update!(status: Outboxer::Message::Status::PUBLISHING)
     message_3.update!(status: Outboxer::Message::Status::FAILED)
-
     header "Host", "localhost"
   end
 
   context "when action is requeue_by_ids" do
-    let(:ids) { [message_2.id, message_3.id] }
-
     before do
       post "/messages/update", {
-        selected_ids: ids,
+        selected_messages: [
+          "#{message_2.id}:#{message_2.lock_version}",
+          "#{message_3.id}:#{message_3.lock_version}"
+        ],
         action: "requeue_by_ids",
         status: :failed,
         page: 1,
@@ -42,12 +41,11 @@ def app
         order: :desc,
         time_zone: "Australia/Sydney"
       }
-
       follow_redirect!
     end
 
     it "queues selected messages" do
-      expect(Outboxer::Models::Message.queued.pluck(:id)).to eq([
+      expect(Outboxer::Models::Message.queued.pluck(:id)).to match_array([
         message_1.id, message_2.id, message_3.id
       ])
     end
@@ -55,19 +53,20 @@ def app
     it "redirects with flash message" do
       expect(last_response).to be_ok
       expect(last_request.url).to include(
-        "messages?status=failed&sort=queued_at&order=desc&per_page=10&time_zone=Australia%2FSydney")
-
+        "messages?status=failed&sort=queued_at&order=desc&per_page=10&time_zone=Australia%2FSydney"
+      )
       expected_flash = URI.encode_www_form_component("success:Requeued 2 messages")
       expect(last_request.url).to include("flash=#{expected_flash}")
     end
   end
 
   context "when action is delete_by_ids" do
-    let(:ids) { [message_2.id, message_3.id] }
-
     before do
       post "/messages/update", {
-        selected_ids: ids,
+        selected_messages: [
+          "#{message_2.id}:#{message_2.lock_version}",
+          "#{message_3.id}:#{message_3.lock_version}"
+        ],
         action: "delete_by_ids",
         status: :failed,
         page: 1,
@@ -76,7 +75,6 @@ def app
         order: :desc,
         time_zone: "Australia/Sydney"
       }
-
       follow_redirect!
     end
 
@@ -87,18 +85,20 @@ def app
     it "redirects with flash message" do
       expect(last_response).to be_ok
       expect(last_request.url).to include(
-        "messages?status=failed&sort=queued_at&order=desc&per_page=10&time_zone=Australia%2FSydney")
+        "messages?status=failed&sort=queued_at&order=desc&per_page=10&time_zone=Australia%2FSydney"
+      )
       expected_flash = URI.encode_www_form_component("success:Deleted 2 messages")
       expect(last_request.url).to include("flash=#{expected_flash}")
     end
   end
 
   context "with invalid action" do
-    let(:ids) { [message_2.id, message_3.id] }
-
     before do
       post "/messages/update", {
-        selected_ids: ids,
+        selected_messages: [
+          "#{message_2.id}:#{message_2.lock_version}",
+          "#{message_3.id}:#{message_3.lock_version}"
+        ],
         action: "invalid",
         status: :failed,
         page: 1,