diff --git a/lib/gocardless_pro/services/payer_authorisations_service.rb b/lib/gocardless_pro/services/payer_authorisations_service.rb
index 5e8a59b..f88d4c8 100644
--- a/lib/gocardless_pro/services/payer_authorisations_service.rb
+++ b/lib/gocardless_pro/services/payer_authorisations_service.rb
@@ -16,6 +16,7 @@ class PayerAuthorisationsService < BaseService
       #
       # @param identity       # Unique identifier, beginning with "PA".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Payer Authorisation is legacy API and cannot be used by new integrators. The Billing Request (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for any new integrations.
       def get(identity, options = {})
         path = sub_url('/payer_authorisations/:identity', {
                          'identity' => identity,
@@ -38,6 +39,7 @@ def get(identity, options = {})
       # solution, such as a multi-step form.
       # Example URL: /payer_authorisations
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Payer Authorisation is legacy API and cannot be used by new integrators. The Billing Request (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for any new integrations.
       def create(options = {})
         path = '/payer_authorisations'
 
@@ -82,6 +84,7 @@ def create(options = {})
       #
       # @param identity       # Unique identifier, beginning with "PA".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Payer Authorisation is legacy API and cannot be used by new integrators. The Billing Request (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for any new integrations.
       def update(identity, options = {})
         path = sub_url('/payer_authorisations/:identity', {
                          'identity' => identity,
@@ -108,6 +111,7 @@ def update(identity, options = {})
       #
       # @param identity       # Unique identifier, beginning with "PA".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Payer Authorisation is legacy API and cannot be used by new integrators. The Billing Request (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for any new integrations.
       def submit(identity, options = {})
         path = sub_url('/payer_authorisations/:identity/actions/submit', {
                          'identity' => identity,
@@ -155,6 +159,7 @@ def submit(identity, options = {})
       #
       # @param identity       # Unique identifier, beginning with "PA".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Payer Authorisation is legacy API and cannot be used by new integrators. The Billing Request (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for any new integrations.
       def confirm(identity, options = {})
         path = sub_url('/payer_authorisations/:identity/actions/confirm', {
                          'identity' => identity,
diff --git a/lib/gocardless_pro/services/redirect_flows_service.rb b/lib/gocardless_pro/services/redirect_flows_service.rb
index 302f692..997abe9 100644
--- a/lib/gocardless_pro/services/redirect_flows_service.rb
+++ b/lib/gocardless_pro/services/redirect_flows_service.rb
@@ -14,6 +14,7 @@ class RedirectFlowsService < BaseService
       # customer to the GoCardless hosted payment pages.
       # Example URL: /redirect_flows
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Redirect Flows are legacy APIs and cannot be used by new integrators. The Billing Request flow (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for your payment flows.
       def create(options = {})
         path = '/redirect_flows'
 
@@ -51,6 +52,7 @@ def create(options = {})
       #
       # @param identity       # Unique identifier, beginning with "RE".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Redirect Flows are legacy APIs and cannot be used by new integrators. The Billing Request flow (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for your payment flows.
       def get(identity, options = {})
         path = sub_url('/redirect_flows/:identity', {
                          'identity' => identity,
@@ -83,6 +85,7 @@ def get(identity, options = {})
       #
       # @param identity       # Unique identifier, beginning with "RE".
       # @param options [Hash] parameters as a hash, under a params key.
+      # @deprecated Redirect Flows are legacy APIs and cannot be used by new integrators. The Billing Request flow (https://developer.gocardless.com/api-reference/#billing-requests) API should be used for your payment flows.
       def complete(identity, options = {})
         path = sub_url('/redirect_flows/:identity/actions/complete', {
                          'identity' => identity,