Why custom codedoesn’t carry overautomatically in atheme update

In short

After a relaunch, Shopify told a client that a new version of his theme was available. The expectation: click, done, like with an app. With a theme that has custom changes, it doesn’t work that way. An update is a new theme version, and your own customizations don’t come along automatically. Our recommendation: only update when there’s a real reason, and then in a planned way.

The case

The client had a purchased theme with several custom modules and tweaks. Shortly after launch, a notice about a new version appeared in the admin, with small design improvements and bug fixes. The question to us: “Can we just install it?”

How theme updates work

An app update replaces software in the background. A theme update works differently: Shopify creates the new version of the theme as a separate copy. Shopify tries to carry over settings from the theme editor, i.e. text, images, colors. Code changes, it doesn’t.

That means: custom modules, customized templates, small code changes are missing from the new version. Simply copying them in doesn’t work reliably, because the structure and building blocks have often changed in the new version.

The live theme stays untouched. So nothing breaks, as long as you don’t publish the new version without testing it.

Our recommendation

• Security and bug-fix updates: install them, in a planned way. Create the new version, transfer your customizations, test, then publish.
• Small design updates: usually ignore them. The effort rarely justifies the benefit.
• Bigger feature updates: bundle them with an upcoming project instead of catching up one by one.

Your takeaways

• Not every update is a must. A theme doesn’t always need the latest version to work well.
• Before every update: make a copy. And only publish the new version once it’s fully tested.
• Get what was customized documented. A short list of your custom modules and changes saves hours at the next update.
• Custom changes belong in their own files. Scattering changes across the theme files makes every update more expensive.

Got a theme update coming up? We’ll tell you whether it’s worth it and transfer your customizations cleanly.