diff --git a/engines/order_management/app/services/order_management/order/updater.rb b/engines/order_management/app/services/order_management/order/updater.rb
index d3c496d4e2..2e4f1c6c4b 100644
--- a/engines/order_management/app/services/order_management/order/updater.rb
+++ b/engines/order_management/app/services/order_management/order/updater.rb
@@ -65,36 +65,20 @@ module OrderManagement
 
       # Updates the +shipment_state+ attribute according to the following logic:
       #
-      # - shipped - when all Shipments are in the "shipped" state
-      # - partial - when 1. at least one Shipment has a state of "shipped"
-      #                       and there is another Shipment with a state other than "shipped"
-      #                  or 2. there are InventoryUnits associated with the order that
-      #                          have a state of "sold" but are not associated with a Shipment
-      # - ready - when all Shipments are in the "ready" state
+      # - shipped - when the order shipment is in the "shipped" state
+      # - ready - when the order shipment is in the "ready" state
       # - backorder - when there is backordered inventory associated with an order
-      # - pending - when all Shipments are in the "pending" state
+      # - pending - when the shipment is in the "pending" state
       #
       # The +shipment_state+ value helps with reporting, etc. since it provides a quick and easy way
       #   to locate Orders needing attention.
       def update_shipment_state
-        if order.backordered?
-          order.shipment_state = 'backorder'
-        else
-          # get all the shipment states for this order
-          shipment_states = shipments.states
-          if shipment_states.size > 1
-            # multiple shiment states means it's most likely partially shipped
-            order.shipment_state = 'partial'
-          else
-            # will return nil if no shipments are found
-            order.shipment_state = shipment_states.first
-            # TODO inventory unit states?
-            # if order.shipment_state && order.inventory_units.where(:shipment_id => nil).exists?
-            #   shipments exist but there are unassigned inventory units
-            #   order.shipment_state = 'partial'
-            # end
-          end
-        end
+        order.shipment_state = if order.shipment&.backordered?
+                                 'backorder'
+                               else
+                                 # It returns nil if there is no shipment
+                                 order.shipment&.state
+                               end
 
         order.state_changed('shipment')
       end
diff --git a/engines/order_management/spec/services/order_management/order/updater_spec.rb b/engines/order_management/spec/services/order_management/order/updater_spec.rb
index 009176eed2..1bd901d37c 100644
--- a/engines/order_management/spec/services/order_management/order/updater_spec.rb
+++ b/engines/order_management/spec/services/order_management/order/updater_spec.rb
@@ -28,22 +28,21 @@ module OrderManagement
       end
 
       context "updating shipment state" do
+        let(:shipment) { build(:shipment) }
+
         before do
-          allow(order).to receive_message_chain(:shipments, :shipped, :count).and_return(0)
-          allow(order).to receive_message_chain(:shipments, :ready, :count).and_return(0)
-          allow(order).to receive_message_chain(:shipments, :pending, :count).and_return(0)
+          allow(order).to receive(:shipments).and_return([shipment])
         end
 
         it "is backordered" do
-          allow(order).to receive(:backordered?) { true }
+          allow(shipment).to receive(:backordered?) { true }
           updater.update_shipment_state
 
           expect(order.shipment_state).to eq 'backorder'
         end
 
         it "is nil" do
-          allow(order).to receive_message_chain(:shipments, :states).and_return([])
-          allow(order).to receive_message_chain(:shipments, :count).and_return(0)
+          allow(shipment).to receive(:state).and_return(nil)
 
           updater.update_shipment_state
           expect(order.shipment_state).to be_nil
@@ -51,18 +50,11 @@ module OrderManagement
 
         ["shipped", "ready", "pending"].each do |state|
           it "is #{state}" do
-            allow(order).to receive_message_chain(:shipments, :states).and_return([state])
+            allow(shipment).to receive(:state).and_return(state)
             updater.update_shipment_state
             expect(order.shipment_state).to eq state.to_s
           end
         end
-
-        it "is partial" do
-          allow(order).
-            to receive_message_chain(:shipments, :states).and_return(["pending", "ready"])
-          updater.update_shipment_state
-          expect(order.shipment_state).to eq 'partial'
-        end
       end
 
       it "state change" do
@@ -93,14 +85,9 @@ module OrderManagement
           updater.update
         end
 
-        it "updates each shipment" do
+        it "updates the order shipment" do
           shipment = build(:shipment)
-          shipments = [shipment]
-          allow(order).to receive_messages shipments: shipments
-          allow(shipments).to receive_messages states: []
-          allow(shipments).to receive_messages ready: []
-          allow(shipments).to receive_messages pending: []
-          allow(shipments).to receive_messages shipped: []
+          allow(order).to receive_messages shipments: [shipment]
 
           expect(shipment).to receive(:update!).with(order)
           updater.update
@@ -120,14 +107,9 @@ module OrderManagement
           updater.update
         end
 
-        it "doesnt update each shipment" do
+        it "doesnt update the order shipment" do
           shipment = build(:shipment)
-          shipments = [shipment]
-          allow(order).to receive_messages shipments: shipments
-          allow(shipments).to receive_messages states: []
-          allow(shipments).to receive_messages ready: []
-          allow(shipments).to receive_messages pending: []
-          allow(shipments).to receive_messages shipped: []
+          allow(order).to receive_messages shipments: [shipment]
 
           expect(shipment).not_to receive(:update!).with(order)
           updater.update
@@ -139,13 +121,9 @@ module OrderManagement
         updater.update
       end
 
-      context "update adjustments" do
-        context "shipments" do
-          it "updates" do
-            expect(updater).to receive(:update_all_adjustments)
-            updater.update
-          end
-        end
+      it "updates all adjustments" do
+        expect(updater).to receive(:update_all_adjustments)
+        updater.update
       end
 
       it "is failed if no valid payments" do