Migrating to a Shopify OS 2.0 Theme in 2025: Checklist, Pitfalls to Avoid, and a Smooth Launch Plan

If you have ever asked how a favorite Shopify store looks so polished and fast, the answer often starts with an Online Store 2.0 theme. In 2025, OS 2.0 is the standard for modular storefronts, app blocks, and flexible content modeling, and it remains the best path to a cleaner codebase and better performance. The conversion stakes are real. Research from Portent indicates that a site that loads in 1 second earns an ecommerce conversion rate 2.5 times higher than a site that loads in 5 seconds, with rates dropping rapidly after the 2 second mark (the analysis covers more than 27,000 landing pages and 100 million page views) according to Portent. Performance is also on Google’s scorecard. The Chrome team confirmed that Interaction to Next Paint replaced First Input Delay as a Core Web Vital in March 2024, which puts more emphasis on responsiveness in your theme and scripts as the web.dev announcement explains.

This guide walks through a pragmatic OS 2.0 migration in 2025. You will get a step by step checklist, the pitfalls that trip teams up, and a calm launch plan. Along the way, use ThemeProbe as your lightweight research buddy. Paste any Shopify store URL to see the theme family instantly at ThemeProbe. No sign up, minimal friction, and your search history lives in local storage so you keep control of what you look up. If research turns into action, you can start building with a free Shopify trial via this quick start link to Shopify.

What migrating to OS 2.0 actually unlocks

Online Store 2.0 is a set of theme features that make stores more flexible to build and maintain, and that reduce entanglement with app code. The official overview notes that OS 2.0 brings JSON templates, “sections on every page,” dynamic sources and metafields, and app blocks that install and uninstall cleanly through theme app extensions as outlined in the Shopify Dev Docs. Shopify also states that upgrading is not mandatory, so you can stay on a vintage theme if it fits your needs, but you miss out on modular sections and modern app integrations if you hold off.

A few capabilities matter most in day to day work:

Sections and blocks everywhere. JSON templates let you add sections to most pages, and merchants can add or remove sections in the editor without a developer per Shopify’s OS 2.0 guide.
Dynamic sources and metafields. You can bind settings to dynamic content and standard metafields, which lets you scale templates across product groups and content types as the developer documentation describes.
App blocks and theme app extensions. Apps can render as blocks inside sections and remove themselves when uninstalled, which avoids the legacy paste code problem as explained in the migration guide.
A performance baseline. Shopify’s performance best practices document highlights that Theme Store submissions must average a Lighthouse score of at least 60 across key templates and that Dawn was built with this in mind according to Shopify’s performance guidance.

If you want the full feature set without manual code work, you can install a new OS 2.0 theme, upgrade your current theme if the developer offers an OS 2.0 version, or convert Liquid templates to JSON by hand the migration assessment summarizes the choices.

Should you migrate in 2025? Use Shopify’s decision framework

Before you touch code, decide your path with Shopify’s official assessment. Shopify recommends three routes: install an OS 2.0 theme, install a new version of your current theme if available, or migrate manually by converting Liquid templates to JSON and moving the necessary Liquid and HTML into sections as described in the migration assessment. The same page calls out factors like the need for OS 2.0 features, current theme satisfaction, app load, budget, and code comfort. If you rely on many apps or have heavy customizations, manual migration might be best so you can bring features over in a controlled way.

Pre migration prep: audit, benchmark, and back up

A calm migration starts with a tidy inventory. Duplicate your theme so you have a safe workspace and a rollback option. Shopify’s tooling and CLI can duplicate themes for you, and the shopify theme duplicate command provides a fast way to copy a theme for development as the CLI command reference shows. Once that draft is created, assemble this short list:

Customizations and content. List custom sections, snippets, and core design patterns you intend to keep. Note metafields in use and any dynamic content that must carry over.
App audit. Inventory apps that inject code or scripts. Check whether each app offers theme app extensions or embeds that work with OS 2.0.
Performance baseline. Record PageSpeed Insights scores and key metrics for home, a collection, and a product page. Note Largest Contentful Paint, Cumulative Layout Shift, and Interaction to Next Paint.
SEO and analytics. Capture title templates, structured data coverage, and pixels. If you embedded scripts directly in theme files or checkout settings, plan to move to the pixels manager.
Markets and languages. Confirm your Markets setup, languages, and hreflang behavior. Shopify automatically adds hreflang and includes published languages in your sitemaps when you use the multi language features per the localization help center guidance.

For inspiration and shortlisting, ThemeProbe is handy here. The ThemeProbe playbook on benchmarking shares a five step process to decode how top stores structure their storefronts and to turn those findings into redesign requirements in the ThemeProbe competitive benchmarking guide. If performance is your goal, the ThemeProbe speed and SEO playbook condenses 30 practical fixes for Core Web Vitals, accessibility, and UX in the ThemeProbe speed and SEO playbook.

The 2025 OS 2.0 migration checklist

Choose your migration path. Decide whether to install a fresh OS 2.0 theme, upgrade to the OS 2.0 version of your current theme, or migrate manually. Shopify’s assessment table simplifies this decision by matching your needs, app load, and budget to a path as the assessment explains.
Create a safe duplicate to work in. Duplicate the live theme or push your code to a draft using Shopify CLI. Keep your draft unpublished until QA is complete the theme duplication command is documented here.
Convert key templates to JSON if migrating manually. Follow Shopify’s step by step guide for converting Liquid templates to JSON, moving code into sections, and defining section order in the new JSON template. Repeat for each template you want to modernize the migration guide walks through each step.
Rebuild sections and blocks with modularity in mind. Create or refactor sections so that merchants can assemble pages through the editor. Add schema settings for blocks and expose only what editors need. This is the moment to simplify. Shopify’s building guidelines for sections and blocks cover best practices and guardrails in the sections and blocks guide.
Enable app blocks and theme app extensions. For sections that should accept app functionality, add support for @app blocks and render them with the correct tags so merchants can place apps from the editor as the migration guide outlines.
Wire up dynamic sources and metafields. Replace hard coded content with metafields so templates can scale across product families and pages. The OS 2.0 docs encourage using standard metafields to increase component reuse see the dynamic sources section.
Rebuild design system and settings. Establish typography, spacing, color tokens, and shared blocks with predictable defaults. If you moved to a new theme, map your previous settings to the new system and avoid one off overrides.
Reinstall apps as embeds and target only necessary templates. Install app blocks and embeds instead of legacy script includes. This keeps scripts out of the global scope and loads functionality only where it is needed as Shopify’s theme app extensions documentation recommends.
Migrate tracking to the pixels manager. Shopify’s pixels manager runs app and custom pixels in a sandbox, centralizes event streams, and improves privacy controls. Avoid injecting raw JavaScript into theme files and use custom pixels or app pixels for GA4, GTM, and ad platforms as the pixels overview explains.
Restore SEO essentials and structured data. Confirm your title and meta defaults, reinstate clean breadcrumb markup, and ensure product JSON LD renders correctly. Shopify’s blog explains how ecommerce schema helps drive rich results, and notes that many themes include product schema while leaving room to add more in Shopify’s schema article.
Internationalization and hreflang. If you sell in multiple languages, verify that your translated URLs and hreflang tags are rendering as expected. Shopify automatically adds hreflang and includes published languages in sitemaps if you use the supported localization features per the help center.
Performance tuning. Apply Shopify’s theme performance best practices. Use responsive images with image_tag, lazy load below the fold, preload only critical assets, limit parser blocking JavaScript, and prefer system fonts where possible as the performance best practices describe. Validate LCP, CLS, and INP in PageSpeed Insights and in Shopify’s Web Performance reports.

Pitfalls to avoid in 2025

Do not sleep on checkout and post purchase changes. Shopify has been moving merchants from legacy page scripts and checkout.liquid toward checkout extensibility. For Shopify Plus stores, August 28, 2025 was the deadline to upgrade Thank you and Order status pages to the new versions using blocks and web pixels. The help center notes that Shopify began shutting down additional scripts, script tag apps, and checkout.liquid on those pages after that date, with auto upgrades set to begin in January 2026 with notice as the Plus upgrade guide explains. Non Plus timelines for other checkout surfaces may vary, so always check your admin notices.

A few more common traps:

Leaving legacy script tags and leftover app code behind. If you uninstall apps, remove their snippets and includes from your theme. Stray includes still load and slow pages. Shopify’s performance guidance explicitly calls out script bloat and remote assets as risks in the best practices document.
Ignoring Core Web Vitals and Lighthouse budgets. Shopify requires a minimum average Lighthouse score of 60 for Theme Store acceptance across key pages as the performance page notes. Portent’s research shows the business impact of slowdowns is steep, with conversion declines for every additional second of load per Portent’s analysis. Plan your UX and scripts around a 1 to 2 second target for top templates where you can.
Structured data regressions. Many themes cover product schema, but collections, breadcrumbs, and articles often go missing in a redesign. Shopify’s schema primer outlines why this matters for rich results and CTR in Shopify’s blog. Validate with Google’s Rich Results Test.
Overlooking international SEO and hreflang. If you switch themes or rename templates, verify that hreflang and language specific URLs still align with your Markets configuration. Shopify documents that hreflang is automatically added and languages are included in sitemaps for supported setups, which is a helpful backstop per the localization help.
Accessibility drift. Recreating fancy layouts while losing focus order, contrast, or alt text support is expensive later. Bake accessible patterns into sections, and validate with Lighthouse and manual keyboard checks. Shopify’s best practices also encourage accessibility as a first class theme concern in the best practices hub.

A smooth launch plan that keeps revenue safe

Treat your OS 2.0 build like a release. The theme editor makes it easy to iterate rapidly, preview templates against specific products or collections, and keep changes isolated until you publish as the theme editor guide shows. A reliable launch plan looks like this:

Stage and preview like a customer. In your draft, wire up key templates and preview with specific products and collections from the theme editor so you confirm variant galleries, buy boxes, and related sections behave with real data the editor supports resource level previews.
Functional QA on every path to purchase. Test navigation, search, collection filtering, product pages, cart, and checkout on mobile and desktop. Validate app blocks and embedded components only appear where needed.
Performance and vitals check. Run PageSpeed Insights on home, a high traffic collection, and a PDP. Look at LCP, CLS, and INP. Confirm that preload tags are limited to critical assets and that heavy scripts are deferred or conditionally loaded. Shopify’s performance page outlines exactly which tactics matter most in themes here.
Pixels sanity check. In the pixels manager, confirm your app pixels and custom pixels are receiving events and respecting consent in configured markets per the pixels overview.
Publish during a low traffic window. Announce a short maintenance window if needed, publish the theme, and watch logs, analytics, and error reporting for the first hour. Keep the previous theme available for instant rollback if you spot a blocker.
Post launch monitoring. Verify conversions, order creation, and pixel events in the first 24 to 72 hours. Review Search Console for crawl or structured data errors and Shopify’s Web Performance reports for field data movement.

Performance quick wins you can ship during migration

Performance usually improves when you simplify and lean into platform defaults.

Use responsive images and native lazy loading. Shopify’s image_tag generates smart srcsets. Lazy load below the fold by passing the loading: 'lazy' attribute as shown in the best practices.
Avoid parser blocking scripts. Add defer or async to non critical scripts and keep custom JavaScript minimal as the performance guidance recommends.
Consider system fonts and limit web font flashes. The performance page calls out system fonts as a way to avoid extra downloads on first paint here.
Preload only what is truly critical. Use Shopify’s preload_tag sparingly for render blocking CSS or your hero image if it determines LCP as described in resource hints.

These moves are small, but shoppers feel them. The Portent dataset shows that each second of delay hurts transactions, and the slice from 1 to 2 seconds is the most sensitive for ecommerce per Portent’s findings. Google’s shift to INP also means your scripts and long tasks need attention so interactions respond under 200 ms on real devices as the INP article advises.

Use ThemeProbe to jump start research and keep it ethical

ThemeProbe is built for curiosity and action. Paste a URL, learn the theme family in seconds, then click through Stores you admire to see common patterns. The ThemeProbe blog has a practical benchmark playbook you can follow to evaluate rivals and translate what works into requirements for your redesign in this guide. If you want a speed checklist for your sprint board, the ThemeProbe speed and SEO playbook lists 30 fixes you can apply during your OS 2.0 build right here.

ThemeProbe keeps the experience lightweight and privacy first. Searches are stored locally in your browser, we use minimal analytics, and acceptable use and affiliate disclosures are spelled out in the Privacy Policy and Terms of Service. When you are ready to build your own store, start a free trial with Shopify and turn inspiration into a live storefront.

Helpful resources

Shopify’s OS 2.0 overview explains sections everywhere, dynamic sources, and app blocks so you know what you are aiming for in the Dev Docs.
The template migration tutorial shows exactly how to convert Liquid templates to JSON and add app block support so you can modernize without guesswork in this guide.
Shopify’s performance best practices set expectations for Lighthouse scores, show how to use image_tag for responsive images, and explain when to preload on this page.
The shift to INP as a Core Web Vital in 2024 means you should test interaction latency and refactor long tasks. The change and diagnostics are summarized by the Chrome team on web.dev.
If you are on Plus and customized Thank you or Order status pages, the 2025 upgrade deadline and impacts are detailed in Shopify’s help center guide here.

When migration is handled with a clear checklist and an honest audit of your apps, content, and pixels, OS 2.0 gives you a faster, easier to maintain theme that helps customers move from discovery to checkout with fewer bumps. Pair a modular theme with a light script footprint, validate Core Web Vitals, and use ThemeProbe as your quick research companion to see what great stores are doing in the wild. If today is the day to start building, spin up your store now with Shopify, then keep your momentum by checking the ThemeProbe blog for playbooks you can run this week.