There is no database upgrade so you just need to load new code

Before start upgrading make sure you are not logged in current version.

• Step 1:  Remove old symfony core
  Before removing files make sure you have database settings which you can find in 'core/config/database.yml'
  Remove all files and folders except 'uploads' folder
   
• Step 2:  Load new files and update database settings
  Just unpack archive in current folder
  Rename databases.yml.sample to databases.yml and update database settings in this file.
  (don't load  databases.yml  from previeous version, just update setting in current file )
  
  note: if db password have special chars then password line in database.yml should be
  password: "<?php echo urlencode('your_db_password') ; ?>"
   
• Step 3: Check Users Groups confiugration
  Version 8.0 have some new configuration
   
• Step 4: Check Tasks Listing configuration
  Just go to Configuration->Tasks->Tasks Listing
  and configure it