Hi Satya
Greetings & Welcome to the Microsoft Q&A forum! Thank you for sharing your query.
The Microsoft. Azure. Cognitive Service. Vision. Face package is currently in its preview version. As of now, there has been no official announcement regarding the release of a stable version. The package has been in preview for an extended period, which suggests that the development team may still be working on enhancements and bug fixes before finalizing a stable release. For updates on the stable version, it is advisable to monitor the official NuGet page or related Microsoft Azure announcements.
We appreciate your patience and understanding. If you have any further questions or need additional assistance, please feel free to contact us.
I hope this helps you. Thank you.