The Course Upgrade tool requires users to review each, individual piece of legacy content to ensure there are no issues when upgrading legacy content. Thus, the Course Upgrade tool will not have an "Approve All" button.
If there were to be an error during the upgrade, it is preferred that users are responsible for approving Upgraded Content. Likewise, we don't want students to be the first to encounter a problem with code that may not have upgraded, as expected.
If users were to select "Approve All," and then go through the content to confirm after, it would be easiest to approve one at a time directly from the Course Upgrade tool.
Assignments, Discussions, Quizzes, and the Syllabus don't have the ability to restore previous versions like pages. It would be dangerous to push a change to these pieces of content without first seeing the upgraded content.
If you do find an error while upgrading content in the Course Upgrade tool, please reach out to our support team by emailing support@cidilabs.com or filling out the Upgrade Support form directly in the Course Upgrade tool.
For more FAQs about the Upgrade tool, see this Knowledge Base Article: Upgrade Tool FAQ.