Updating Your Shopify Theme
Occasionally we will roll out changes to our premium themes to fix bugs and add new features, but those changes are not automatically added to your store. Currently, Shopify does not have a manual or automatic way to update your installed themes.
The best way to go about updating your theme is to download the premium theme to manually add Liquid changes or republish it to your store. Since it is not a straightforward process we will always publish theme changelogs so you know exactly what has changed. Plus we are always happy to help you on the details of the changes if you send us a message.
Shopify Manual: When a designer rolls out changes to a theme, how do I enable the theme updates?