How to update shopify theme?
Step – 1 : Download latest package from themeforest and Upload new theme on your store but do not publish yet.
Step – 2 : Now Go to current version ( published theme ) => Click on Action => Edit Code => Config => settings_data.json – Copy all content from this file ( ctrl+a, ctrl+c)
Step – 3 : Open same file in new version ( New uploaded theme) => Remove all content and simple paste new copied code here. (ctrl + v)
Step – 4 : Save page then check theme in preview mode of new version if everything is working, you can publish new theme version.
Please Note: Customization work and app settings will get overwrite did in template files. You need to do it manually to move code from old version to new version.