Will I lose my customizations if I update my Shopify theme?

If you bought the theme from the Shopify Theme Store, updating it keeps your theme settings, your page layouts, your section and block content, any templates you created, and your app embeds. The one thing that can fail to carry over is direct edits to the theme code, and Shopify tells you explicitly which of the two happened.

If you uploaded the theme yourself, from a ZIP or a third party developer, the question does not apply in the same way. Those themes get no update mechanism at all. Installing a newer version means uploading it as a separate theme and setting it up from scratch.

What carries over when you update a Shopify theme?

Shopify's update flow does not overwrite your live theme. It builds a new draft called "Updated copy of" your theme, migrates what it can into that copy, and leaves your published theme untouched until you publish the new one yourself.

After the update runs, the confirmation reads either "Theme added: code edits successfully included" or "Theme added: code edits could not be included". That message is the whole answer to this question. Everything in the rows above it has already been handled.

Where do my customizations actually live?

Understanding why settings survive is easier once you know they are not stored in the theme's code files at all. They sit in a small number of JSON files that the theme reads at render time, which is exactly why they can be lifted out of one version and dropped into the next.

We parsed 28 complete generated Shopify themes in our own build archive on 20 September 2026. Every one of them stores its customizable state in the same two places.

So the typical theme in our archive carries about 72 stored values across 12 files. That is the entire surface an update has to migrate, and it is small precisely because a theme's code is deliberately kept separate from a merchant's choices.

The 23 global settings were identical in structure across all 28 themes: 13 text fields, 6 colors, 2 image pickers (logo and favicon), 1 range and 1 checkbox, grouped under Colors, Typography, Logo, Social media, Reviews, Popup and Favicon. The template side is where the volume is. Across the 28 themes we counted 481 section instances holding 934 setting values, and 534 blocks holding another 1,170. Blocks hold more stored content than sections do, which matches what a store actually looks like: one testimonial row, many testimonials. We wrote about that split in the difference between a section and a block.

Why are code edits the only thing at risk?

Because a code edit changes a file the theme author also changes. When you rewrite a line in sections/header.liquid and the author rewrites the same area in the new version, there is no rule that decides who wins, so Shopify does not guess. It attempts a merge, and if the two sets of changes touch the same ground, it hands you the updated theme without your edits and says so.

Settings never hit this problem. A value in settings_data.json is keyed by a setting id, and as long as the new version still defines that id, the value slots straight back in. The failure mode there is different and much quieter: if the author renamed or deleted a setting, its stored value has nowhere to go and the new theme falls back to that setting's default. Nothing errors. The color just looks different.

The practical rule is worth stating plainly. Before you update, write down what you changed in the code. Shopify will tell you if the edits could not be included, but it will not tell you what they were.

How do I update a theme without breaking my store?

1. Check whether the theme came from the Shopify Theme Store. Only those get the "Update available" banner. Themes from third party marketplaces or uploaded as a ZIP are updated by the developer, or not at all.
2. Duplicate your live theme first. This costs nothing and gives you a known good copy to publish if the update goes badly.
3. Note your code edits. If you opened the code editor at any point, list the files you touched before you start.
4. Run the update. Click the banner, read the release notes, and choose Add to draft themes. Your published theme is not touched.
5. Read the confirmation. It says whether code edits were included. If they were not, reapply them to the draft copy by hand.
6. Preview the draft properly. Open the homepage, a collection page, a product page, the cart and the search page. Check each at phone width as well, because a layout regression on mobile is the one nobody catches from a desktop preview.
7. Publish the draft when it looks right. Keep the old theme in your library for a week before deleting it.

Step 2 and step 7 both consume slots in your theme library, which is capped. Stores on Basic, Grow and Advanced can hold 20 themes, and Shopify Plus stores can hold 100. Published and draft themes both count, so a store that has been collecting backups for a year can hit the ceiling mid update and have to delete something first.

What if I uploaded the theme myself?

Then there is no update to run, and that is the honest answer for most themes outside the Theme Store, including the ones this site generates. An uploaded ZIP becomes a new, separate theme in your library. It does not inherit the settings of the theme sitting next to it, because settings_data.json and the JSON templates belong to each theme individually.

What that means in practice: if you upload version two of a theme you have already set up, you are setting up 23 theme settings and roughly 49 section and block values again. Not catastrophic, but not free either, and it is the reason to make code edits sparingly on a theme you expect to replace.

It is worth separating this from the other worry people usually have at the same time. Your products, collections, customers, orders and pages live in your store's database, not in the theme, and none of them are affected by any of this. We covered that in full in will I lose my products if I change my Shopify theme.

The related surprise is that a fresh theme shows placeholder content rather than the demo you previewed, which is a separate mechanism again and catches almost everyone: why your store does not look like the theme demo.

Should I update at all?

Usually yes, and the reason is not features. Theme updates carry accessibility fixes, checkout and app compatibility changes, and adjustments for new Shopify storefront capabilities that older section schemas cannot express. A theme two years behind tends to fail in ways that look like app bugs rather than theme bugs.

The case for waiting is narrow: heavy code customization plus a busy sales period. If your theme has meaningful code edits and you are inside a launch or a seasonal peak, run the update into a draft anyway so you know what you are dealing with, and publish it afterwards.

How we measured this

The per theme counts on this page come from parsing config/settings_schema.json and every file in templates/ across 28 complete generated Shopify themes in our build archive, on 20 September 2026. That is 644 global settings, 280 JSON templates, 481 section instances, 534 blocks and 2,104 stored setting values, with zero parse failures. Per theme figures use the median, because a small number of the 28 are unusually content heavy and pull the mean up: the range of stored template values runs from 49 to 224.

What carries over during an update, the "Updated copy of" naming, the two code edit messages and the theme library limits are Shopify's own documented behaviour, not our measurements.

If you want to see what a filled in theme looks like before you commit to setting one up twice, every theme in our free theme gallery has a live preview with its sections and blocks already populated.