diff --git a/app/models/transfer_request.rb b/app/models/transfer_request.rb
index a2a06da9d3..90e26f3734 100644
--- a/app/models/transfer_request.rb
+++ b/app/models/transfer_request.rb
@@ -59,6 +59,7 @@ class TransferRequest < ApplicationRecord # rubocop:todo Metrics/ClassLength
     state :processed_1
     state :processed_2
     state :processed_3
+    state :processed_4
     state :failed, enter: :on_failed
     state :passed
     state :qc_complete
@@ -81,18 +82,22 @@ class TransferRequest < ApplicationRecord # rubocop:todo Metrics/ClassLength
       transitions to: :processed_3, from: [:processed_2]
     end
 
+    event :process_4 do
+      transitions to: :processed_4, from: [:processed_3]
+    end
+
     event :pass do
       # Jumping straight to passed moves through an implied started state.
       transitions to: :passed, from: :pending, after: :on_started
-      transitions to: :passed, from: %i[started failed processed_2 processed_3]
+      transitions to: :passed, from: %i[started failed processed_2 processed_3 processed_4]
     end
 
     event :fail do
-      transitions to: :failed, from: %i[pending started processed_1 processed_2 processed_3 passed]
+      transitions to: :failed, from: %i[pending started processed_1 processed_2 processed_3 processed_4 passed]
     end
 
     event :cancel do
-      transitions to: :cancelled, from: %i[started processed_1 processed_2 processed_3 passed qc_complete]
+      transitions to: :cancelled, from: %i[started processed_1 processed_2 processed_3 processed_4 passed qc_complete]
     end
 
     event :cancel_before_started do
diff --git a/features/support/capybara.rb b/features/support/capybara.rb
index 9844a37be4..d94270e497 100644
--- a/features/support/capybara.rb
+++ b/features/support/capybara.rb
@@ -13,12 +13,7 @@
   options.add_argument('--headless')
   options.add_argument('--window-size=1600,3200')
   options.add_preference('download.default_directory', DownloadHelpers::PATH.to_s)
-  the_driver = Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
-
-  # the following is needed to avoid a test failure where the driver would
-  # forget / ignore its configured download location on every other run
-  the_driver.browser.download_path = DownloadHelpers::PATH.to_s
-  the_driver
+  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
 end
 
 Capybara.register_driver :chrome do |app|
diff --git a/spec/models/state_changer/initial_stock_tube_spec.rb b/spec/models/state_changer/initial_stock_tube_spec.rb
index 82d6180ebe..4fb18fc1fc 100644
--- a/spec/models/state_changer/initial_stock_tube_spec.rb
+++ b/spec/models/state_changer/initial_stock_tube_spec.rb
@@ -256,6 +256,30 @@
         expect(request.reload.state).to eq('started')
       end
     end
+
+    context 'when transitioning to "processed_4" with "started" requests' do
+      let(:target_state) { 'processed_4' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "processed_4" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('processed_4')
+        expect(request.reload.state).to eq('started')
+      end
+    end
+  end
+
+  context 'when the tube is: "processed_4"' do
+    let(:transfer_request_state) { 'processed_4' }
+
+    context 'when transitioning to "passed" with "started" requests' do
+      let(:target_state) { 'passed' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "passed" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('passed')
+        expect(request.reload.state).to eq('started')
+      end
+    end
   end
 
   context 'when the tube is: "passed"' do
diff --git a/spec/models/state_changer/mx_tube_spec.rb b/spec/models/state_changer/mx_tube_spec.rb
index 81d1dc221b..791f1945de 100644
--- a/spec/models/state_changer/mx_tube_spec.rb
+++ b/spec/models/state_changer/mx_tube_spec.rb
@@ -296,6 +296,30 @@ def create_requests_and_transfers
         expect(request.reload.state).to eq('passed')
       end
     end
+
+    context 'when transitioning to "processed_4" with "started" requests' do
+      let(:target_state) { 'processed_4' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "processed_4" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('processed_4')
+        expect(request.reload.state).to eq('started')
+      end
+    end
+  end
+
+  context 'when the tube is: "processed_4"' do
+    let(:transfer_request_state) { 'processed_4' }
+
+    context 'when transitioning to "passed" with "passed" requests' do
+      let(:target_state) { 'passed' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "passed" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('passed')
+        expect(request.reload.state).to eq('passed')
+      end
+    end
   end
 
   context 'when the tube is: "passed"' do
diff --git a/spec/models/state_changer/stock_tube_spec.rb b/spec/models/state_changer/stock_tube_spec.rb
index 8803714d1c..30708aecb7 100644
--- a/spec/models/state_changer/stock_tube_spec.rb
+++ b/spec/models/state_changer/stock_tube_spec.rb
@@ -297,6 +297,30 @@
         expect(request.reload.state).to eq('started')
       end
     end
+
+    context 'when transitioning to "processed_4" with "started" requests' do
+      let(:target_state) { 'processed_4' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "processed_4" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('processed_4')
+        expect(request.reload.state).to eq('started')
+      end
+    end
+  end
+
+  context 'when the tube is: "processed_4"' do
+    let(:transfer_request_state) { 'processed_4' }
+
+    context 'when transitioning to "passed" with "started" requests' do
+      let(:target_state) { 'passed' }
+      let(:request_state) { 'started' }
+
+      it 'updates the tube to "passed" with "started" requests', :aggregate_failures do
+        expect(transfer_request.reload.state).to eq('passed')
+        expect(request.reload.state).to eq('started')
+      end
+    end
   end
 
   context 'when the tube is: "passed"' do
diff --git a/spec/models/transfer_request_spec.rb b/spec/models/transfer_request_spec.rb
index ca58fffa08..fffbe6e8aa 100644
--- a/spec/models/transfer_request_spec.rb
+++ b/spec/models/transfer_request_spec.rb
@@ -269,7 +269,8 @@
         started: :passed,
         failed: :passed,
         processed_2: :passed,
-        processed_3: :passed
+        processed_3: :passed,
+        processed_4: :passed
       },
       process_1: {
         pending: :processed_1
@@ -280,6 +281,9 @@
       process_3: {
         processed_2: :processed_3
       },
+      process_4: {
+        processed_3: :processed_4
+      },
       qc: {
         passed: :qc_complete
       },
@@ -289,6 +293,7 @@
         processed_1: :failed,
         processed_2: :failed,
         processed_3: :failed,
+        processed_4: :failed,
         passed: :failed
       },
       cancel: {
@@ -296,6 +301,7 @@
         processed_1: :cancelled,
         processed_2: :cancelled,
         processed_3: :cancelled,
+        processed_4: :cancelled,
         passed: :cancelled,
         qc_complete: :cancelled
       },
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index bdb9b6d4fe..c7373c133e 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -52,17 +52,14 @@
 
   options.add_argument('--headless')
   options.add_preference('download.default_directory', DownloadHelpers::PATH.to_s)
-  the_driver = Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
-
-  # copied the following over from features/support/capybara.rb because I expect it is also relevant here
-  the_driver.browser.download_path = DownloadHelpers::PATH.to_s if the_driver.browser.respond_to?(:download_path=)
-  the_driver
+  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
 end
 
 Capybara.register_driver :selenium_chrome do |app|
-  driver = Capybara::Selenium::Driver.new(app, browser: :chrome)
-  driver.browser.download_path = DownloadHelpers::PATH.to_s
-  driver
+  options = Selenium::WebDriver::Chrome::Options.new
+
+  options.add_preference('download.default_directory', DownloadHelpers::PATH.to_s)
+  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
 end
 
 Capybara.javascript_driver = ENV.fetch('JS_DRIVER', 'headless_chrome').to_sym