Good to know about the update
The update will not cause any disruption to the online store, as it will be done in several stages. For practical instructions on how to perform the update, see below.
The old version will be kept safe, and you can always revert to it if necessary.
The update does not always automatically copy the changes made to the theme. In larger updates, the theme will revert to the default settings, and in smaller updates, the changes you make will be copied automatically.
Changes made to the theme's source code are not copied. You should copy them manually from the old version of the theme and check that the changes work correctly in the new one.
Installing and checking the update
Go to Online Store section.
Click the blue Actions-link on the top left corner and select Update.
Once the theme has been updated, it will appear in the theme library (further down on the page), and from there you can:
Preview the updated theme by choosing Actions > Preview.
Edit the theme by clicking on the Edit button.
Check that the new updated version looks and works as intended.
Publishing the updated version
Once the update is done, you can publish it.
Click the Action > Publish button under the theme.
A new Publish theme button will appear on the right.
Click the Publish theme button to make the theme public in your online store.