Vienna is a freeware, open source RSS/Atom newsreader for the Mac OS X operating system. It provides features comparable to commercial newsreaders, but both it and the source code are freely available for download.

Features:

• Subscribe to Atom/RSS news feeds and podcasts.
• Simple and intuitive user interface with customisable toolbar.
• Built-in tabbed browser.
• Global search of all retrieved articles.
• Automatic detection of newsfeeds on web pages.
• Smart folders for organising related feed articles.
• Custom article display styles.
• Three separate reading layouts.
• Blogging integration.
• Support for downloading enclosures in articles
• Filter the displayed articles.
• Manual reordering of the subscription list.
• Full AppleScript support.
• Localised into several languages.

Requirements:
OS X 10.11+
Universal Binary