Upgrading Moodle database from version 2.4 (Build: 20121203) (2012120300.00) to 2.7.20 (Build: 20170508) (2014051220.00)

Your Moodle files have been changed, and you are about to automatically upgrade your server to this version:

2.7.20 (Build: 20170508) (2014051220.00)

Once you do this you can not go back again. Please note that this process can take a long time.

Are you sure you want to upgrade this server to this version?