This update now includes two different add-ons. One is compatible with XF 2.0 and the other is compatible with XF 2.1.
The instructions have also been changed to avoid errors when accessing the install system in XF 2.0.
This change also introduces a slightly changed approach to avoid the repeated code when setting up the AWS SDK client.
The XF 2.1 version of the add-on also does not require the autoloader stuff to be applied as the add-on does that automatically. However, note that until XF 2.1 Beta 3 the install system may still not work. You will need to comment out all of the S3 related code before accessing the install system.