The official release of Umbraco 12 is due at the end of June 2023 with the most prominent addition being the new Content Delivery API. There is already a release candidate available for Umbraco 12 and we've also made sure to provide a release candidate for Newsletter Studio.
The feature set and functionalities are the same as in earlier versions.
Try the RC today1
Just install using your favorite NuGet-tool
dotnet add package NewsletterStudio --version 12.0.0-rc1