*** Updating 1
1. On old site
Go to Customize -> Theme actions -> Import demo -> Scroll down to where as this image and click to Copy all data in Export’box
2. On new site
Go to Customize -> Theme actions -> Import demo. Paste all of data from Old theme to Import’box of New theme -> Import and Save
Result: On new update get all config from old theme
*** Updating 2: you can update by another way:
** On old site
Go to Customize -> Theme actions -> Edit code
Open settings_data.json of theme -> Copy all code.
** On new site
Go to Customize -> Theme actions > Edit code. Paste all code from Old theme to settings_data.json in New theme -> Save.
Result: On new update get all config from old theme