diff --git a/src/pages/docs/platform/account/enterprise-customization.mdx b/src/pages/docs/platform/account/enterprise-customization.mdx
index fcc16822dc..90be556fcb 100644
--- a/src/pages/docs/platform/account/enterprise-customization.mdx
+++ b/src/pages/docs/platform/account/enterprise-customization.mdx
@@ -123,6 +123,10 @@ Repeat this step for all fallback hosts in the `fallbackHosts` array, if provide
 
 Now that you have tested your custom endpoints, you must modify your code to instantiate the Ably client with the provided `ClientOptions`.
 
+<Aside data-type='note'>
+If you are using an SDK that does not yet support the `endpoint` client option, or are on an older version of an SDK that does, use the [legacy options](#legacy-options) instead.
+</Aside>
+
 The following example demonstrates how to set up the Ably Realtime client using an [Ably subdomain:](#option-1)
 
 <Code>
@@ -153,6 +157,37 @@ You should then test that all client SDKs can connect, publish, and receive mess
 
 Where possible, you should also inspect your network traffic to verify that the client SDKs are calling the endpoints for your custom endpoint. Instead of connections to `realtime.ably.net` you should see connections to `[ENDPOINT].realtime.ably.net`, or your own custom CNAME domain.
 
+### Use legacy client options <a id="legacy-options"/>
+
+If your SDK version does not support the `endpoint` client option, use the following legacy options instead.
+
+The following example demonstrates how to set up the Ably Realtime client using an [Ably subdomain:](#option-1)
+
+<Code>
+```javascript
+const ably = new Ably.Realtime({
+  authUrl: '/auth', // Your authentication URL
+  environment: 'example-eu', // Replace with your custom endpoint name
+});
+```
+</Code>
+
+The following example demonstrates how to set up the Ably Realtime client using [your own subdomain:](#option-2)
+
+<Code>
+```javascript
+const ably = new Ably.Realtime({
+  authUrl: '/auth', // Your authentication URL
+  restHost: 'realtime.ably.example.com',
+  realtimeHost: 'realtime.ably.example.com',
+  fallbackHosts: [
+    'a.fallback.ably.example.com',
+    'b.fallback.ably.example.com'
+  ]
+});
+```
+</Code>
+
 ### Roll out your changes <a id="roll-out"/>
 
 Once all your client library SDKs are using the new endpoint and traffic is arriving at the correct endpoints, the team at Ably will be able to actively reroute your traffic based on your endpoint settings.