Hey Ivj,
There isn't a change log, per se. When Armagan releases a new version, he usually states in the release post, the major changes that have been made.
Since you would be upgrading from version 0.6xx to 0.704 ... there have been numerous changes.
I would offer a suggestion of downloading the full 0.704 version and installing it into a different folder. That way you can try it out and see the differences that have been made without overwriting your older version.
Hope that helps,
Narcissus