There are a few steps you should take before you proceed to migrate to the new templates.
Step 1 - Understand the benefits of the new templates
The most important step is to understand the benefits of moving to the new templates. While there are benefits, for existing merchants there is also worked involved in migrating in order to preserve all of the content from your existing store as you move to the new templates.
Step 2 - Copy all global variables with content
When you use the Design Wizard, new templates with new variables will be installed to your store. For this reason all global variable information will be deleted from your current templates. If you have added content you wish to preserve to your variables, you will want to copy this information prior to using the Design Wizard. Learn more.
Note: Variable overrides on specific sections or items in your store will be maintained when you migrate. The variables may no longer be used however, so be sure to check your pages after migrating.
Step 3 - Make note of pages with custom types
While custom types will be migrated when you move to the new templates, all pages in your store will use the default page types after migrating. You will then need to reset pages to your custom type. Learn more.
Note: If you migrated to the new templates before performing these steps, you can contact Customer Care to request a rollback to your previous templates at the time you migrated.