You must have administrator access to do this. 
Login to Admin Area.

To turn RSS feeds on

• Click on Settings menu
• Choose the Public Area -> Common tab
• Go to the section titled RSS Feeds at the bottom of the screen
• In the Generate RSS feeds field choose either One Channel for whole knowledgebase, or Channel for every top category depending on whether you want multiple feeds or one feed for the whole knowledgebase.
• Click Save to implement the changes.

To turn RSS feeds off

• Click on Settings menu
• Choose the Public Area -> Common tab
• Go to the section titled RSS Feeds at the bottom of the screen
• In the Generate RSS feeds field choose Do not generate any RSS feeds
• Click Save to implement the changes.