How to change your Shopify theme without breaking your apps
How to change your Shopify theme without breaking apps: turn on app embeds, re-add app blocks and code edits, test, then publish.
Shopify setup guides
Theme changes, app embeds and store setup, from the team that supports thousands of Shopify stores.
Short answer
Most "my app stopped working" problems on Shopify come from the theme, not the app. When you switch themes, each app's app embed and app blocks have to be turned on again in the new theme, and code edits from the old theme don't carry over.
Changing themes
How to change your Shopify theme without breaking your apps is the checklist: add the new theme unpublished, turn on app embeds, re-add app blocks and code edits, then test before you publish.
When app fields don't show
Why app options or upload fields don't show starts with the 30-second fix, turning on the app embed in the theme you're viewing, then works through the rest.
All Shopify setup guides
Why app options or upload fields don't show on your Shopify theme
App options or upload fields missing? Turn on the Shopify app embed in the theme you're viewing, then work through these checks.