For the last fixed version (2.x) the code is public and is available at the following directory of our code repository:
branches/pandora_2.x . You can download it through the Subversion client using the following command:
svn co https://pandora.svn.sourceforge.net/svnroot/pandora/branches/pandora_2.x
You will only need to copy the new files onto the old ones. PLEASE MAKE SURE to create a backup of everything (including the database), just to be sure.
While you’re at it, consider the convenience of using the Pandora Enterprise version: