JARRv3 comes a bunch of improvements :

• New API, entierly testable at api.jarr.info/
• Improved control of clustering
• Integration with rss-bridge to ease feed creation for website that doesn't provide RSS
• JSON feed support
• Better UI feeling, quicker and responsive UI (thanks to @clarissecarzon)
• Improved filters to tinker with you feed content
• Auto integration of article linking youtube videos or images