Upgrade StarSquid

This guid covers some of the breaking changes in StarSquid. For a more comprehensive list, please refer to the changelog.

Most of the changes are related to the new Astro v6, which is a major release with many breaking changes. We have made sure that StarSquid(2.0.0 or later) is compatible with Astro v6, but there are some changes that you need to be aware of when upgrading your site.