add latest realtime voice limitations

Author: bryantanderson

fern/openai-realtime.mdx

@@ -5,7 +5,7 @@ slug: openai-realtime
 ---
 
 <Note>
-  The Realtime API is currently in beta, and not recommended for production use by OpenAI. We're excited to have you try this new feature and welcome your [feedback](https://discord.com/invite/pUFNcf2WmH) as we continue to refine and improve the experience.
+  The Realtime API is currently in beta, and not recommended for production use by OpenAI. Advanced functionality is currently limited with the latest voices Ash, Ballad, Coral, Sage and Verse. We're excited to have you try this new feature and welcome your [feedback](https://discord.com/invite/pUFNcf2WmH) as we continue to refine and improve the experience.
 </Note>
 
 OpenAI’s Realtime API enables developers to use a native speech-to-speech model. Unlike other Vapi configurations which orchestrate a transcriber, model and voice API to simulate speech-to-speech, OpenAI’s Realtime API natively processes audio in and audio out.