Several of my Webflow sites use Style Guide 1.4, and I want to update them to Style Guide 2.1.
I would be very careful in migrating from 1.X to 2.X - I would say generally, our advice would be to not migrate. We've done a lot of work on our end to ensure that the components in the library are backwards compatible. So its just a matter of selecting your preferences and going from there.
However, if you truly want to migrate, I would make sure to take backups or maybe duplicate a project and test it out in that duplicate first. You can see a full changelog of what was changed from CF v2.0 to CF v2.1 here on the changelog section of our announcement post. https://library.relume.io/whats-new/january-component-day#webflow-style-guide-updates