Sorry. I should knew I didn't provide more details. The migration I will take is not only changing the platforms, but also the content. The new WP site (is up & running on a temp domain) has new directory structure, new content, and new database. So yes, the whole site structure will be different, because that is how the new site is designed by some guy/team in my office's headquarter. But still, I can just 301-redirect all the links in my old site's sitemap to the new site. Right? Thanks for the answer.