Simplify the following text for a Grade 9 native English-speaking person.
Original: Existing users of the 2006 , 2007 , 2008 or 2009 versions can upgrade to the latest version of the Norton software without buying a new subscription .
Simplified: Existing users of the 2006 , 2007 , or 2008 versions can upgrade to the latest 2009 version without buying a new subscription .