Hello,
Thanks for reaching out! Unfortunately this is not something that is currently a feature of any of our premium plugins. Users can subscribe via RSS as you mentioned, but this would be the extent of the built-in subscription functionality.
If this is a feature that you would like to see added in the future, please do let us know over in our Feature Ideas Forum! This is what we use to gauge user interest in new features and help guide future development efforts.
I’m sorry I don’t have a better answer for you at the moment, but if you have any other questions, please let me know!
Thanks,
Jennifer