RSS feed is an awesome feature that is now added in Subscribers Elite plan and with this feature, you can now automatically send push notification to your Subscribers whenever a new blog content is published on your site.
Here's how you can add the RSS feed in Subscribers.
1) First, you need to obtain the RSS feed URL of your website and to do that, simply go to your website and right click on the website’s page, and choose Page Source. In the new window that appears, use the “find” feature (Ctrl + F on a PC or Command + F on a Mac), and type in RSS. You’ll find the feed’s URL between the quotes after href=. ( See screenshot below)
-For WORDPRESS, just simply add /feed to URL, for example, website.com/feed.
2) Copy the URL and go to your Subscribers dashboard then navigate to "Notification"> "RSS Feed".
3) Click "Add New RSS" and you'll then be prompted with additional important instructions. 
4) Put an RSS Feed name and paste the RSS feed URL,
5) Select to either automatically send a push notification for every new blog by leaving the "Create Draft" option OFF or turning it ON to create a new draft notification of each new blog published rather than sending it automatically.
6) Click the "Save RSS Feed" button and you're all set!