Remove dead code: Order#backordered?

app/models/spree/order.rb

@@ -203,10 +203,6 @@ module Spree
       total.to_f > 0.0 && !skip_payment_for_subscription?
     end
 
-    def backordered?
-      shipments.any?(&:backordered?)
-    end
-
     # Returns the relevant zone (if any) to be used for taxation purposes.
     # Uses default tax zone unless there is a specific match
     def tax_zone

engines/order_management/spec/services/order_management/order/updater_spec.rb

@@ -8,8 +8,6 @@ module OrderManagement
       let(:order) { create(:order) }
       let(:updater) { OrderManagement::Order::Updater.new(order) }
 
-      before { allow(order).to receive(:backordered?) { false } }
-
       context "updating order totals" do
         before do
           2.times { create(:line_item, order: order, price: 10) }