docs: more clarity on features list

Author: dphang

README.md

@@ -50,7 +50,9 @@ With a simplified architecture and no use of CloudFormation, there are no limits
 
 ### Features
 
-The following shows all supported features or planned features. Is there a feature that you want but is not yet supported? Please open a [new issue](https://github.com/serverless-nextjs/serverless-next.js/issues/new?assignees=&labels=&template=feature_request.md&title=) to let us know!
+The following shows all supported features or planned features. If the checkbox is ticked, it means that the feature is supported. Otherwise, it is likely not supported yet or currently in planning or in implementation stage. Please refer item's description for specific details.
+
+Is there a feature that you want but is not yet supported? Please open a [new issue](https://github.com/serverless-nextjs/serverless-next.js/issues/new?assignees=&labels=&template=feature_request.md&title=) to let us know!
 
 - [x] [Server side rendered pages at the Edge](https://github.com/zeit/next.js#fetching-data-and-component-lifecycle).
       Pages that need server side compute to render are hosted on Lambda@Edge. The component takes care of all the routing for you so there is no configuration needed. Because rendering happens at the CloudFront edge locations latency is very low!