mozimo.in/docs/research/shopify-admin-operations-facts.md

# Shopify admin operations: product CSV round-trip fidelity + customer accounts system (verified 2026-10-13)

**Purpose.** Two focused factual questions, answered only from Shopify-owned primary sources:

1. What survives a **manual admin product CSV export → import round trip** between two Shopify stores,
   in particular product metafields.
2. Which **customer accounts system** the merchant's `Settings > Customer accounts` page describes, and
   the lifecycle/plan facts around new vs legacy customer accounts.

**Facts only. No recommendations.**

**Store context** (from the parent task and the sibling note
[shopify-cart-probe-2026-10.md](shopify-cart-probe-2026-10.md)): `mozimo.in`, shop GID
`gid://shopify/Shop/74467967222`, 61 products each with exactly one variant, 16 collections, 20 products
with nutrition/ingredient metafields.

---

## 0. How this was verified (and one method finding worth reusing)

* **`shopify.dev`:** every page was fetched as raw Markdown by appending `.md` to the HTML URL
  (e.g. <https://help.shopify.com/en/manual/products/import-export/export-products.md>), which the site
  itself documents as available for any page.
* **`help.shopify.com` — the 403 was bypassed by the same `.md` suffix.** Bare help-centre URLs return
  HTTP **403** with `<title>Verifying your connection...</title>` (Shopify's bot challenge) for `curl`,
  for the `web_fetch` tool, and regardless of `User-Agent` (tested: default `curl`, Chrome desktop,
  Safari desktop, Googlebot). Appending `.md` to the **same** URL returns **HTTP 200 with the complete,
  untruncated raw Markdown article**. Confirmed pairs, same second:

  | URL | HTTP |
  | - | - |
  | `https://help.shopify.com/en/manual/products/import-export/export-products` | **403** |
  | `https://help.shopify.com/en/manual/products/import-export/export-products.md` | **200** (8,029 bytes) |

  A locale-prefixed path is required: `/en/manual/...`. Bare `/manual/...` (no `/en`) also **403**s.
  This was used for essentially every `help.shopify.com` claim below, so the impact of the bot challenge
  on this research was **zero**.
* **The official sample product CSV was downloaded from the help centre**:
  <https://help.shopify.com/csv/product_template.csv> → HTTP 200, 6,536 bytes, 61 header columns.
  Its header row and example rows are quoted verbatim in [§1.3](#13-what-is-actually-in-the-exported-file-headers)
  and [§1.5](#15-variants-and-the-title--default-title-question). Note: the canonical URL without the
  `/en` prefix works for this asset (`/csv/product_template.csv`), while `/en/csv/product_template.csv`
  returns the HTML app shell, not the CSV.
* **Shopify changelog** (`https://shopify.dev/changelog/...` and `https://changelog.shopify.com/posts/...`)
  — the latter supports no `.md` (HTTP 406) and was extracted from its HTML.
* **Shopify community forums** were read via the forum's own JSON API
  (`https://community.shopify.com/t/<id>.json`, `https://community.shopify.dev/t/<id>.json`,
  `.../search.json?q=`). These are **not** documentation; every community claim below is labelled as such
  and is never used as the sole support for a fact that a primary source could carry.
* **What is marked UNVERIFIED** is listed inline and collected in [§3](#3-verification-notes-and-gaps).

---

# Question 1 — Product CSV export/import round-trip fidelity

## 1.1 The exact export click path, and the export options

Source: <https://help.shopify.com/en/manual/products/import-export/export-products>
(<https://help.shopify.com/en/manual/products/import-export/export-products.md>).

Admin path and options, verbatim from the doc:

1. Go to **Products** (<https://admin.shopify.com/products>).
2. Click **Export**.
3. In the dialog, choose the products:
   * the current page of products
   * **All products**
   * products you have **selected**
   * products that match your **search and filters**
4. Choose the file type:
   * **CSV file for Excel, Numbers, or another spreadsheet program** — "if you plan to use a spreadsheet
     program to edit your product CSV file"
   * **Plain CSV file** — "if you plan to use a plain-text editor"
5. Click **Export products**.

**How the file reaches you (this is conditional, and matters for a 61-product store):**

| Situation | Delivery |
| - | - |
| **All products** selected | CSV is **emailed** to you; if you aren't the store owner it is also emailed to the store owner |
| **Current page** or **Selected products**, and **any single product has >100 variants** | CSV is **emailed** |
| **Current page** or **Selected products**, and **all products have <100 variants** | CSV is **downloaded by your browser** |

Same source (`.md`, "Export your products" preamble).

**Only one file is produced** — a single products CSV. There is no second artefact and no image bundle.
No doc states the filename; **UNVERIFIED** (the docs never name the downloaded/emailed file).

**Encoding:** "A CSV file with UTF-8 encoding is the only file format that can be used to import to or
export from Shopify." (same source, "Use a text editor to edit your products CSV file").

## 1.2 Filtered export (relevant if the export must be split)

1. On **Products**, add a filter so only the wanted products are listed.
2. Export, selecting the option that exports **only the products matching your filter**.

Source: <https://help.shopify.com/en/manual/products/import-export/export-products.md>.
A documented export failure mode for large files: *"There was an error exporting your products. Try again
in a few minutes"* indicates the export timed out (thousands of variants); the documented workaround is to
filter and export smaller subsets (same source, "Troubleshooting product exports").

## 1.3 What is actually in the exported file (headers)

The docs publish the full column list at
<https://help.shopify.com/en/manual/products/import-export/using-csv#csv-file-description>.

The **official sample CSV** (<https://help.shopify.com/csv/product_template.csv>, fetched 2026-10-13)
carries this exact header row, 61 columns, quoted verbatim:

```
Title,URL handle,Description,Vendor,Product category,Type,Tags,Published on online store,Status,SKU,Variant Barcodes,Option1 name,Option1 value,Option1 Linked To,Option2 name,Option2 value,Option2 Linked To,Option3 name,Option3 value,Option3 Linked To,Price,Compare-at price,Cost per item,Charge tax,Tax code,Unit price total measure,Unit price total measure unit,Unit price base measure,Unit price base measure unit,Inventory tracker,Inventory quantity,Continue selling when out of stock,Weight value (grams),Weight unit for display,Requires shipping,Fulfillment service,Product image URL,Image position,Image alt text,Variant image URL,Gift card,SEO title,SEO description,Color (product.metafields.shopify.color-pattern),Google Shopping / Google product category,Google Shopping / Gender,Google Shopping / Age group,Google Shopping / Manufacturer part number (MPN),Google Shopping / Ad group name,Google Shopping / Ads labels,Google Shopping / Condition,Google Shopping / Custom product,Google Shopping / Custom label 0,Google Shopping / Custom label 1,Google Shopping / Custom label 2,Google Shopping / Custom label 3,Google Shopping / Custom label 4,Packed product length,Packed product width,Packed product height,Packed product dimension unit
```

Two further header sources exist and do **not** agree word-for-word with either the sample or the current
documentation — see [§1.5](#15-variants-and-the-title--default-title-question) and
[§1.9](#19-other-things-that-silently-fail-or-are-commonly-lost):

* A **legacy** header list is still published in the help centre's import-troubleshooting article:
  `Handle,Title,Body (HTML),Vendor,Type,Tags,Published,Option1 Name,Option1 Value,...,Image Src,Image Alt Text`
  (<https://help.shopify.com/en/manual/products/import-export/common-import-issues.md>, "Invalid CSV
  header: missing headers"). The authoritative current list on the same help centre is the `using-csv`
  one cited above; the article itself notes Shopify *"maintains backward compatibility with older column
  names"* (<https://help.shopify.com/en/manual/products/import-export/using-csv.md>).
* **Market columns** are appended conditionally: *"If you have **Markets** set up on your store, then your
  CSV export includes columns for some of your markets... `Included / [Market]`, `Price / [Market]`,
  `Compare At Price / [Market]`."* A market gets columns only if exactly one of its active catalogs isn't
  shared with another market. The primary market always appears as `Included / [Primary]` and the default
  international market as `Included / International` (same source, "International CSV columns"). So a
  Mozimo export is **not** exactly 61 columns; it carries extra market columns.

## 1.4 The exact import click path, and how the import behaves

Source: <https://help.shopify.com/en/manual/products/import-export/import-products>
(<https://help.shopify.com/en/manual/products/import-export/import-products.md>).

1. Go to **Products**.
2. Click **Import**.
3. Click **Add file**, select the CSV.
4. *Optional:* deselect **Publish new products to all sales channels** to publish new products only to the
   online store.
5. *Optional:* select **Overwrite products with matching handles**.
6. Click **Upload and continue**.
7. **Review the details about the import**, then click **Import products**.

**Is it a background job?** The doc describes an upload → review → confirm flow, followed by a
**confirmation email from Shopify**, and an **activity log** you can check afterwards. It never calls it a
"background job". It does say explicitly: *"Product imports started with a CSV file can't be canceled once
they begin, and you can't view a history of past imports. To review recent changes made by an import,
check your store's activity log."* A separate note states that after upload *"you receive a confirmation
email from Shopify to the email address of your user account"* (same source, "Import products from
another store"). **UNVERIFIED:** the doc does not state whether processing continues after the admin tab
is closed, nor any progress/status surface beyond the email and activity log.

**Dry run / preview?** There is a step 7 "Review the details about the import". The docs do **not**
describe it as a data preview, a row-level validation report, or a dry run — the phrase is "details about
the import". **No documented dry-run/preview exists.** **UNVERIFIED** what that review screen lists.

**How errors are reported.** Documented error surface is (a) a set of named error messages, and (b)
per-line messages. From <https://help.shopify.com/en/manual/products/import-export/common-import-issues.md>:

* `Daily variant creation limit reached, try again` — for stores with ≥500,000 variants (excluding Plus),
  max **10,000 new variants per 24 hours** created by CSV uploads or API; the 24-hour timer starts at the
  first upload of the day.
* `Fulfillment service can't be blank` — must be a fulfilment-service name, or `manual`.
* `Ignored line #-## because handle 'example' already exists` — "The handle is used to uniquely identify
  each individual product."
* `Ignored line #-## because it did not contain product data` — a handle with no product title.
* `Illegal quoting on line`, `Missing or stray quote on line`, `Unexpected characters or symbols`
  (non-UTF-8 encoding), `Network error: Unexpected token < in JSON at position 0` (column headers don't
  match the template exactly; **headers are case-sensitive**, e.g. `Handle` not `handle`),
  `Not a valid product category`, `Inventory quantity can't be blank`, `Inventory quantity is not a
  number`, `Inventory policy is not included in the list`, `Validation failed: price can't be blank`,
  `Validation failed: options are not unique`, `Import fails with error "Line is invalid (No details)"`.
* Image-specific validation failures: `Validation failed: An error occurred while trying to download the
  image` ("An image file is missing") and `Validation failed: getaddrinfo: nodename nor servname provided,
  or not known` (image URL needs `http://`/`https://` and a publicly accessible direct link) — same source.

**Is it idempotent? Does re-importing update by handle or duplicate?** This is documented precisely
(<https://help.shopify.com/en/manual/products/import-export/using-csv#overwriting-csv-file> and the
`import-products` page):

* **With `Overwrite products with matching handles` selected:** *"when the handle in the import CSV file
  matches an existing handle in your products list, the values in the CSV file overwrite the values in the
  matching columns in the existing product list."*
  → re-running the same file **updates** existing products; it does not create duplicates.
* **Without that option selected:** *"the products that match an existing handle are ignored during CSV
  import."*
  → re-running the same file is a no-op for those products, not a duplicate generator.
* The `Ignored line #-## because handle ... already exists` error message corroborates handle-as-key
  (<https://help.shopify.com/en/manual/products/import-export/common-import-issues.md>).
* A conflicting handle **inside one file** also fails: *"Ignored line #-## because handle `example`
  already exists"*.
* **CSV cannot bulk-delete products** — use bulk actions in **Products**
  (<https://help.shopify.com/en/manual/products/import-export/using-csv#overwriting-csv-file>).

**File limit:** *"Your product CSV can't exceed 15 MB."* If the upload errors or times out, split the file
(<https://help.shopify.com/en/manual/products/import-export/import-products.md>).

**Required columns.** Importing new products: only `Title` (plus `URL handle` if adding variants).
Updating products: `URL handle` and `Title`. Header names are case-sensitive.
(<https://help.shopify.com/en/manual/products/import-export/using-csv.md>, "Required columns in the
product CSV file".)

**Not a migration tool for anything else.** Nothing in the product CSV docs covers customers, orders,
discounts, gift cards, or files.

## 1.5 Variants, and the `Title` / `Default Title` question

**Representation.** One row per variant, with the product-level data repeated on the first row and only
the handle repeated on subsequent rows. The docs describe two shapes
(<https://help.shopify.com/en/manual/products/import-export/using-csv.md>, "Create your product CSV file"):

* *"Simple product: A simple product doesn't include variants. If you upload a product that doesn't have
  variants, then enter all the fields for the product in the first row along with the URL for the first
  image. In the following rows, only enter the handle and the URL for each additional image."*
* *"Product with variants: ... enter all the fields for the product in the first row along with the URL for
  the first image. In the following rows, enter the URL handle. Then skip the Title, Description, Vendor,
  and Tags columns. Fill out the rest of the variants' details and each image URL."*

The option columns are `Option1 name` / `Option1 value` / `Option1 Linked To`, up to `Option3`
(case in the current docs: `Option1 name`; the sample CSV also uses `Option1 name`). Up to 3 options per
product (same source, column table).

**On the merchant's exact shape (61 products, one variant each, option name `Title`):** the published
guidance is internally inconsistent, and this is the single most quotable wrinkle found:

| Source | What it says for a one-option product |
| - | - |
| Current column reference, `Option1 name` row: *"If a product has only one option, then this value should be `Default Title`."* | **`Default Title`** — <https://help.shopify.com/en/manual/products/import-export/using-csv.md> |
| **Official sample CSV** (`/csv/product_template.csv`), row 16, product `Example Perfume` | `Option1 name = Title`, `Option1 value = Premium` — i.e. option name `Title` with an **arbitrary** value |
| Also in the sample, `Title` is used as the option *name* for the single-option product, while multi-option products use `Size`/`Color`/`Format` (verbatim rows quoted in this file's own `python3 csv` alignment, from the downloaded sample) | **`Title`** |
| Community help article (Shopify-staff-authored account, but a forum post, 2023-05-09): *"Change the Option1 Name column value to Title and the Option1 Value column value to Default Title."* | **`Title` + `Default Title`** — <https://community.shopify.com/t/214856.json> |

So the docs' `Default Title` instruction is about the **value**; the sample uses `Title` as the **name**.
The merchant's stored shape (option name literally `Title`) is exactly the shape the official sample CSV
represents. Consequence for the round trip:

* Re-importing an **unmodified export** reproduces the exported shape by construction — the export writes
  whatever the store holds, and import consumes the same columns. **UNVERIFIED:** no primary source
  states, for this admin, the literal string an *export* writes into `Option1 value` for a one-variant
  product whose option name is `Title`. The only way to establish it is to read the merchant's own export.
* Real risk documented around the option columns, not around the name itself:
  * *"Changing data in the `Option1 value`, `Option2 value`, or `Option3 value` columns of the product CSV
    file deletes existing variant IDs, and creates new variant IDs."*
  * *"If you don't include the `Option1 name` and `Option1 value` columns, then a new default variant is
    created and existing variants are deleted."*
  * *"If a non-required column is included in the import CSV file that relies on other column data not
    included in the file, then existing data is deleted or removed. For example, if the `SKU` column is
    included in the import CSV file, but not the `Option1 value` and `Option1 name` columns, then the
    product variant option is deleted."*
  * Option-name conflicts fail the whole import with `Line is invalid (No details)`; the documented
    workaround is a temporary option name in a first import, then a second import to rename.
  * *"Validation failed: options are not unique."*
  All from <https://help.shopify.com/en/manual/products/import-export/using-csv.md> and
  <https://help.shopify.com/en/manual/products/import-export/import-products.md>.

## 1.6 METAFIELDS — do `custom.ingredients` / `custom.energy_kcal` survive? **Yes, with conditions.**

**Short answer.** Product metafields **do** travel in the product CSV and are a first-class part of the
documented CSV column set — but only metafields that have a **definition**, and the round trip is a
two-part operation: (1) definitions in the destination store, (2) the values, which ride in the CSV. There
is **no separate metafield CSV file** in the admin. Variant metafields are **excluded** from product CSV
entirely.

**Primary source:** <https://help.shopify.com/en/manual/products/import-export/using-csv.md>
(§"Metafields in CSV columns", §"Variant metafields", and the `Metafields` row of the column table) —
the same page saved as raw Markdown at
<https://help.shopify.com/en/manual/products/import-export/using-csv.md>.

Verbatim facts:

1. *"Product metafields are supported in product bulk import/export using CSV files. **After a product
   metafield is defined, it's included in your product CSV exports.**"*
2. Header format: `<name>` (`product.metafields.<namespace>.<key>`) — e.g.
   `Fabric (product.metafields.shopify.fabric)` — **or** bare `product.metafields.<namespace>.<key>`.
   The sample CSV carries a live example column: `Color (product.metafields.shopify.color-pattern)`.
   The column-table row repeats the format as `NAME; (product.metafields.custom.KEY)`.
   The namespace/key are found in **Settings > Custom data > Products** (same page).
   → For the merchant: `custom.ingredients` and `custom.energy_kcal` appear as
   `Ingredients (product.metafields.custom.ingredients)` and `Energy kcal (product.metafields.custom.energy_kcal)`
   (the display name is the definition's name; the parenthesised identifier is authoritative).
3. **Supported metafield types in CSV bulk import/export** (verbatim list): `boolean`, `color`
   (`#ff00cc`), `date`, `date_time`, `dimension` (`25.0cm`), `list.color`, `list.date`, `list.date_time`,
   `list.dimension`, `list.metaobject_reference`, `list.number_decimal`, `list.number_integer`,
   `list.product_reference`, `list.url`, `list.volume`, `list.weight`, `money` (`5.99 CAD`),
   `multi_line_text_field`, `number_decimal`, `number_integer`, `product_reference`, `shopify.disclosure`,
   `single_line_text_field`, `url`, `volume`, `weight`.
   * `custom.ingredients` as text → `multi_line_text_field` (**supported**; example given is literally
     `"Ingredients\nFlour\nWater\nMilk\nEggs"`).
   * `custom.energy_kcal` as a number → `number_integer` or `number_decimal` (**supported**).
4. **Variant metafields do NOT round-trip.** Verbatim: *"Variant metafields aren't supported for product
   CSV import/export. To edit your variant metafields in bulk, you need to use the variant bulk editor,
   and then add metafield columns."* → <https://help.shopify.com/en/manual/products/import-export/using-csv.md>;
   bulk editor how-to at <https://help.shopify.com/en/manual/custom-data/metafields/bulk-edit-metafields.md>.
5. **Definition-before-value requirement.** *"Metafield definitions act as templates that specify what part
   of your store a metafield applies to and what values the metafield can have. **Before you can add
   metafield values to specific products... you need to add the metafield definition for that
   information.**"* — <https://help.shopify.com/en/manual/custom-data/metafields/metafield-definitions.md>.
   Definitions live at <https://admin.shopify.com/metafields>; up to 256 definitions per type.
   The CSV page's phrasing *"after a product metafield is defined, it's included in your product CSV
   exports"* means an **undefined** product metafield is not guaranteed to appear as a column, and the
   docs never state what happens to an undefined metafield's *value* during import.
   → Treat "metafield values with no matching definition in the destination store" as **UNVERIFIED /
   not documented**. (A community thread on 2026-09-24 reports category-linked metafields being added as
   columns for products with a category — <https://community.shopify.com/t/686939.json> — but it is a
   forum post, not documentation.)
6. **No separate metafield export/import file or step exists in the admin.** The metafields help section
   (<https://help.shopify.com/en/manual/custom-data/metafields.md>) lists no export/import feature; its
   bulk tooling is the admin bulk editor ("Editing metafields in bulk": *"You can use the bulk editor tool
   to make changes to multiple metafields at the same time. You can edit metafields in bulk for products,
   variants, collections, and customers."*), which edits in place and does not produce a file.
   → The product CSV **is** the supported admin mechanism for moving product metafield values.
7. **Overwrite semantics apply to metafield columns too, and they are destructive.** With
   **Overwrite products with matching handles** on: *"If a non-required column in the import CSV file is
   blank, then the matching value in the product list is overwritten as blank."* So a blank metafield cell
   in an overwrite import **clears** the destination value
   (<https://help.shopify.com/en/manual/products/import-export/using-csv.md#overwriting-csv-file>).
8. **Metaobjects are not exported as content.** Metafield *references* to metaobjects are supported as
   identifiers (`list.metaobject_reference` accepts GIDs or handles), but no doc says metaobject
   definitions/entries travel in the product CSV. **UNVERIFIED** and not mentioned anywhere in the CSV or
   metafields help pages.

**Metafield-only alternative for moving values between stores:** the docs describe no file-based
alternative in the admin. The developer-surface option is the GraphQL Admin API
`metafieldsSet` (<https://shopify.dev/docs/api/admin-graphql/latest/mutations/metafieldsSet>) with
`MetafieldDefinition` creation (<https://shopify.dev/docs/api/admin-graphql/latest/input-objects/MetafieldDefinitionInput>),
and Shopify's metafields developer guide (<https://shopify.dev/docs/apps/build/metafields>,
<https://shopify.dev/docs/apps/build/custom-data/metafields>). This note records only that these exist;
no recommendation is made.

## 1.7 Images

**Primary source:** <https://help.shopify.com/en/manual/products/import-export/using-csv.md>
("Prepare your images", "Adding multiple product images in a CSV file", and the `Product image URL`,
`Image position`, `Image alt text`, `Variant image URL` rows) and
<https://help.shopify.com/en/manual/products/import-export/export-products.md> ("Access your product
image files").

* **The CSV carries image URLs, not image bytes.** Columns: `Product image URL`, `Image position`,
  `Image alt text`, `Variant image URL`. *"A CSV file can only contain text, therefore, you need to make
  sure that all product images are on an existing website. Those image URLs are only used during the CSV
  file importing process. You can delete the URLs after your import is complete."*
* **Import re-hosts the image.** *"Enter the URL for the product image. **Shopify downloads the images
  during the import and re-uploads them in your store.**"* → a `cdn.shopify.com` URL from the source store
  is fetched and copied into the destination store.
* **The source store must stay alive and its images publicly reachable until the import completes** —
  this is the documented failure mode for exactly the migration case in question:
  * *"When you export your products, the images associated with each product aren't included in the CSV
    file. If you import the products to a new store, then the product images are generated only if they
    remain viewable on a publicly accessible website."*
  * *"To ensure that your product images remain accessible to you, leave your original store and its
    products intact until you finish the import process."*
  * *"If you remove products or product images from your Shopify store after exporting, and then try to
    import those products without updating their image URLs, then your import will fail."*
  * *"Your product images must be uploaded to a publicly accessible URL. That is, they should be behind an
    `https://` protocol with no password protection."*
  * Documented image errors: `Validation failed: An error occurred while trying to download the image`
    ("An image file is missing"), `Validation failed: getaddrinfo: nodename nor servname provided, or not
    known` (malformed URL / not a direct public link), and `Incorrect header check` — *"Remove the image
    from that line and try again. If that resolves the issue, then try hosting the image somewhere else."*
    (<https://help.shopify.com/en/manual/products/import-export/common-import-issues.md>).
* **Alt text survives** — `Image alt text` is a first-class column. Max 512 characters, optimal ≤125.
* **Image order survives** via `Image position` (ascending, starting at 1). One row per image.
* **Filename constraints on import:** the image file name *"is final: you can't edit it after the image has
  been uploaded to your store"* and must not contain `_thumb`, `_small`, or `_medium` suffixes.
* **Cap and media types:** up to **250 images per product**; *"You can use only image URLs in CSV files.
  3D models and videos aren't supported for the CSV."*
* **Files-area duplication:** importing an image that lives in the destination's **Content > Files** area
  *"is redownloaded and duplicated"* (the copy lands in `/products/`, the original stays in `/files/`;
  documented as expected behaviour).
* **Rate limits on the image fetch:** **UNVERIFIED.** No primary source found stating a per-import image
  fetch rate limit or concurrency cap.
* **Community-reported (not documentation) silent image loss:** a 2026-08-07 forum post from a
  vendor-affiliated CSV-tool account describes images vanishing after an import that reported "Success",
  attributing it to the background image-ingestion step
  (<https://community.shopify.com/t/396027.json>). Treat as unverified anecdote; note that its author
  advertises a competing tool.

## 1.8 Collections — **NOT in the export. This is a real gap.**

**Primary source:** <https://help.shopify.com/en/manual/products/import-export/using-csv.md>
("Collection column exception").

* *"When you export a CSV file, the `Collection` column isn't included."* — collections and membership are
  **absent** from the product CSV export.
* The **only** supported CSV route is a hand-added column on **import**:
  * *"The `Collection` column is the only column that you can add to the CSV file that doesn't break the
    format. You can't add any other columns to your CSV file."*
  * Header must be exactly `Collection`; it can go anywhere in the file.
  * *"Enter the name of the collection that you want to add this product to."*
    * *"If it's an existing collection that has conditions, then the product needs to meet the conditions
      for the collection."*
    * *"If the collection doesn't already exist, then a collection is created."*
  * **Hard limit: *"You can add a product to only one collection."*** Value may be blank; max length 255
    characters.
* Consequence for a 16-collection catalogue with products in more than one collection: the CSV can only
  express one membership per product. (Multiple rows for the same handle collide with the
  handle-uniqueness rule that produces `Ignored line #-## because handle ... already exists` —
  <https://help.shopify.com/en/manual/products/import-export/common-import-issues.md>.)
* **Supporting context on the collections model:** a new collections model is replacing legacy manual and
  smart collections; where it is available, previous collections were auto-converted. Collections can be
  populated by manual inclusion, inclusion conditions, manual exclusion, and exclusion conditions, and can
  nest. Collections are managed at <https://admin.shopify.com/collections>. Smart/conditional collections
  self-populate from conditions, so membership is reproducible by conditions rather than by a file.
  Source: <https://help.shopify.com/en/manual/products/collections.md> and
  <https://help.shopify.com/en/manual/products/collections/create-collection.md>.
* **The only documented bulk membership mechanism for a product in many collections is the admin bulk
  editor** (<https://help.shopify.com/en/manual/shopify-admin/productivity-tools/bulk-editing.md>,
  reachable from **Products** → select products → **Edit products**), or the GraphQL Admin API
  (`collectionAddProducts` / `CollectionInput`; collection reference:
  <https://shopify.dev/docs/api/admin-graphql/latest/objects/Collection>).
  There is **no** documented collection export/import file (no collections CSV in the help centre, and
  **UNVERIFIED** whether one exists anywhere in the admin).

## 1.9 Other things that silently fail or are commonly lost

All from <https://help.shopify.com/en/manual/products/import-export/using-csv.md> unless noted.

| Field | Round-trip behaviour |
| - | - |
| **Status (active/draft/archived)** | `Status` column. *"If this column is present, then it needs a value. If the column isn't present, then the product status is automatically uploaded as `active`."* Blank `Status` with a present column → import error surface (`Status` requires a value). |
| **Published on online store** | `Published on online store` column, `true` (default) / `false`, governs only the **online store** sales channel. |
| **Sales-channel publication beyond online store** | *"CSV files can't be used to bulk update product availability on other sales channels."* The import dialog's **Publish new products to all sales channels** checkbox (default on) is the only channel control, and it applies to **new** products only — deselect it to publish new products to the online store only (<https://help.shopify.com/en/manual/products/import-export/import-products.md>). Per-channel availability must be set in the admin or by API. |
| **SEO title / SEO description** | Both columns exist and round-trip, with a documented caveat: *"The SEO Title and SEO Description fields in exported CSV files are only populated when you've manually customized them in your products. If these fields haven't been edited, then they'll be blank in the export. This is expected behavior, as the CSV can only export saved data. When these fields are blank, SEO information is automatically generated based on your product title and description."* (<https://help.shopify.com/en/manual/products/import-export/export-products.md>). Limits: SEO title ≤70 chars, SEO description ≤320 chars (using-csv). On import, blank SEO title → product `Title` used; blank SEO description → product `Description` used. |
| **Weight** | `Weight value (grams)` (numeric grams only, no unit, no decimals — e.g. 5125 for 5.125 kg) and `Weight unit for display` (`g`/`kg`/`lb`/`oz`; default `kg`). Default value 0 if blank. |
| **Inventory quantity** | `Inventory quantity` — *"This applies only to Shopify stores that have a single location."* Default 0 if blank. For multi-location stores the docs route you to the **inventory CSV** (<https://help.shopify.com/en/manual/inventory-and-locations/setup/inventory-csv>) or the Inventory API. |
| **Inventory tracker** | `Inventory tracker` = `shopify`, `shipwire`, `amazon_marketplace_web`, or blank if untracked. *"If existing inventory tracking options are removed, then inventory is no longer tracked."* On export, third-party-fulfilment variants show `manual` (or `gift_card` for gift-card variants); `Inventory tracker` shows `shopify` when tracking is on and is blank when it isn't (<https://help.shopify.com/en/manual/products/import-export/export-products.md>). |
| **Tolerances** | `Continue selling when out of stock` = `deny` (default) / `continue`. `Charge tax` and `Requires shipping` are boolean columns. `Cost per item` exists. |
| **Tags** | `Tags` column; max 250 tags/product; comma-separated in one cell, quoted; *"Tags aren't case sensitive."* |
| **Product type** | `Type` column — free-form label, round-trips. |
| **Product category** | `Product category` — must match Shopify's Standard Product Taxonomy breadcrumb or ID exactly, else `Not a valid product category`. |
| **Handle** | `URL handle` is the join key for overwrite behaviour; must be unique across the file. Changing it changes the product URL. |
| **SKU / barcodes** | `SKU` (required non-blank with a custom fulfilment service) and `Variant Barcodes` (up to 20, semicolon-separated, optional `type:` prefix). A file containing **both** `Barcode` and `Barcodes` columns fails to import. |
| **Gift cards** | `Gift card` column exists and can bulk-edit details, but *"you can't create a gift card by importing a product CSV file."* |
| **Media** | Videos and 3D models are **not** in the CSV (images only). |
| **Dimension columns** | `Packed product length/width/height` + `Packed product dimension unit` exist. |
| **Sorting the CSV in a spreadsheet** | *Caution:* *"Sorting your CSV file in a spreadsheet program can cause product variants or image URLs to become disassociated. Importing a CSV file that has been sorted might overwrite your existing products with bad data, which can't be recovered."* (export doc) / *"Importing a CSV file that has been sorted by a spreadsheet editor such as Microsoft Excel or Apple Numbers might cause your products to be removed from their relevant image links on the CSV, and your product's images will be lost."* (import doc). |
| **Excel delimiter trap** | *"If you use Excel to edit your CSV, then check Excel's export settings when you export the CSV to ensure that your file uses commas between values."* |
| **Backward-compatibility of column names** | *"If you use an older CSV template, then you might have different column names than the ones that are listed on this page. Shopify maintains backward compatibility with older column names, but you should consider updating to the current format."* |
| **Overwrite side effects** | Blank non-required cell overwrites the destination value **as blank**; an omitted column leaves the destination value unchanged; including a column whose dependencies are absent deletes/removes data. |
| **Import limits** | 15 MB file cap; 10,000 new variants/24h for stores with ≥500,000 variants (excluding Plus); can't be cancelled; no import history; review via activity log. |
| **Single-location assumption** | Both the sample-file note and the `Inventory quantity` row tie the CSV's quantity field to single-location stores. **UNVERIFIED:** no doc says what happens to `Inventory quantity` on import into a multi-location store (the docs only redirect to the inventory CSV / Inventory API). |

---

# Question 2 — New vs legacy customer accounts, from admin UI evidence

## 2.1 Which system does that UI describe? **New customer accounts.** (Two independently primary legs.)

The evidence quoted for the merchant's admin page is from the parent task's description: a **Sign-in
links** toggle, a **Customer accounts** section with **Configurations / Customize** and **Authentication /
Manage**, **Self-serve returns** (off), **Store credit** (on), and a **URL** row with **Change domain**
showing `https://shopify.com/74467967222/account`.

**Leg A — feature availability.** The help centre's own comparison table marks **Self-serve returns** and
**Store credit** as available in **Customer accounts** and **not** available in **legacy customer
accounts** (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade/compare-features.md>):

| Feature | Customer accounts (new) | Legacy customer accounts |
| - | - | - |
| Self-serve returns | ✔ | ✘ |
| Store credit | ✔ | ✘ |
| Saved payment methods | ✔ | ✘ |
| Branding source | checkout settings | **online store theme settings** |
| Customisation model | app blocks in a visual editor | **"Requires editing Liquid code"** |
| Sign-in | one-time 6-digit email code; optional Shop / Google / Facebook | **email + password**; separate register page or invite |

The same page: *"There are two versions of customer accounts: **Customer accounts** is the newest version
... **Legacy customer accounts** lets your customers sign in using an email and a password."*

**Leg B — the documented admin surface.** The help centre documents the **new** system's settings page as
exactly the set of rows on the merchant's screen. *"From your Shopify admin, go to **Settings > Customer
accounts** to manage more settings:"* — **Self-serve returns**, **Store credit**, **URL**, **Social
sign-in**, **Sign in with Shop**, **Identity provider**; plus the **Sign-in links** section with the *Show
sign-in links* toggle; plus "Configuring apps and branding for customer accounts" pointing at the
**checkout and accounts editor**
(<https://help.shopify.com/en/manual/customers/customer-accounts/manage.md>):

* *"In the **Sign-in links** section, do either of the following: To display sign-in links on your store,
  toggle on **Show sign-in links**."*
* *"Use the checkout and accounts editor to configure brand settings and add more features with apps. You
  can also customize the experience by market. You can work on your configuration in draft before
  publishing."* — and "Settings > Checkout > **Configurations** > **Customize**" is the documented route
  into that editor
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>, Steps 2–4).
* The Admin GraphQL object mirrors this page field-for-field: **`Shop.customerAccountsV2`** exposes
  `customerAccountsVersion` (`CLASSIC` | `NEW_CUSTOMER_ACCOUNTS`), `loginLinksVisibleOnStorefrontAndCheckout`,
  `loginRequiredAtCheckout`, and `url` ("The root url for the customer accounts pages")
  (<https://shopify.dev/docs/api/admin-graphql/latest/objects/CustomerAccountsV2.md>,
  <https://shopify.dev/docs/api/admin-graphql/latest/enums/CustomerAccountsVersion.md>).

**Contrast with the legacy surface:** legacy customisation lives in **theme** templates, not a settings
page with feature toggles. The upgrade guide has you review *"Online Store > ... > Edit theme ... **Legacy
customer accounts**"* and `templates/customers` Liquid files (`customers/account.liquid`,
`customers/login.liquid`, `customers/register.liquid`), and it describes the new system as *"Managed
independently from your theme"* (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>).
The official deprecation announcement likewise groups *"Legacy customer account liquid templates"* as the
legacy artefact (<https://community.shopify.dev/t/legacy-customer-accounts-availability-update/31724>).

**Note on the admin's actual words.** The `shopify.dev` getting-started guide for the Customer Account API
describes an older/alternate settings layout — *"Under **Accounts in online store and checkout** section,
click on **Edit**. Choose **Customer accounts**. Click **Save**"* — which does **not** match the merchant's
row set, and shows that Shopify has more than one wording for this panel
(<https://shopify.dev/docs/storefronts/headless/building-with-the-customer-account-api/getting-started.md>).
That mismatch is itself a signal that the merchant's panel is the newer layout, but it makes the
**"Sign-in links" toggle alone non-diagnostic**: the toggle is a new-system control, yet no primary source
was found that says legacy stores cannot also see a sign-in-links row.
**UNVERIFIED:** whether a store on legacy accounts can see a *Sign-in links* row in this panel.

## 2.2 What `https://shopify.com/<numeric-id>/account` indicates

**New customer accounts use `shopify.com/<shop-ID>/account` by default. Classic/legacy accounts do NOT use
that format — but a legacy store can *display* it in settings.**

**New system, verbatim:**

* *"By default, your customer accounts pages, such as the sign-in page, the orders page, and the profile
  page, use a `shopify.com` URL format as their base domain, similar to `shopify.com/1234567890/account`
  with a unique ID number for your store. For example, the sign-in link at the top of your store is
  something similar to `shopify.com/authentication/1234567890/login`, and the URL for the main orders page
  could be similar to `shopify.com/1234567890/account/orders`. This also includes the Order status page."*
  — <https://help.shopify.com/en/manual/customers/customer-accounts/customize-customer-accounts/connect-domain-customer-account.md>
* *"In the **Customer accounts** section, the **URL** field displays a preview of the current URL. Click
  **Change domain**."* — same page. The merchant's `URL` row with **Change domain** is this control.
* *"If you didn't set up a subdomain, then the default format is `https://shopify.com/{your-store-ID}/account`."*
  — <https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>, Step 8.

The numeric ID is the shop ID: the sibling probe note establishes `gid://shopify/Shop/74467967222` for this
store ([shopify-cart-probe-2026-10.md](shopify-cart-probe-2026-10.md)), and the merchant's URL is
`https://shopify.com/74467967222/account`. The number matches.

**Legacy system URLs are on the store's own domain.** The docs never show a `shopify.com/<id>/account`
URL for legacy accounts; legacy account pages are `customers/*` theme templates served on the storefront
(`/account`, `/account/login`, etc.), and *"Your legacy customer account pages, such as the sign-in page,
keep their existing URLs until you complete the upgrade."* — same `connect-domain-customer-account` page.

**The caveat that makes the URL merely strong, not conclusive on its own:**

* The upgrade guide has you configure and **publish** the new customer-accounts configuration, and set a
  custom subdomain, *before* the actual cutover: *"Your online store and checkout still link to legacy
  customer accounts until you complete Step 9."* The URL in **Settings > Customer accounts** is therefore
  populated for stores that are mid-migration and still serving legacy pages to customers
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>).
* *"If you're still using legacy customer accounts, then you can set up your subdomain before you upgrade
  to the latest version of customer accounts. Setting up your subdomain first means that your customer
  account pages use your own domain as soon as you upgrade, instead of a `shopify.com` URL."* — and
  *"The Order status page is the exception. It uses the new subdomain as soon as you set the subdomain as
  the primary domain"* (<https://help.shopify.com/en/manual/customers/customer-accounts/customize-customer-accounts/connect-domain-customer-account.md>).
* The upgrade guide describes an **Upgrade** banner button on **Settings > Customer accounts** for stores
  that still need to cut over: *"Click **Upgrade** in the banner at the top of the page."*
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>, Step 9).
  *The parent's description of the page does not mention an Upgrade banner, which is consistent with an
  already-upgraded store — but this note did not observe the page directly.*

## 2.3 Grow plan: new customer accounts and the Customer Account API

**New customer accounts on Grow: no plan gate was found, and the system is the only one still available.**

* The plan gate that **is** documented for this area is **not** new customer accounts itself. The only
  "Plan requirement" aside on the customer-accounts settings page is for **Saved payment methods**:
  *"Saved payment methods are available only to stores that use Shopify's Enterprise offering, including
  commerce components, and have customer accounts set up."*
  (<https://help.shopify.com/en/manual/customers/customer-accounts/manage.md#saved-payment-methods>).
  Separately, **Identity provider** is *"available only to stores on the Shopify Plus plan"*
  (<https://help.shopify.com/en/manual/customers/customer-accounts/sign-in-options/identity-provider.md>),
  and **Multipass** is Plus-only
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>).
* New customer accounts is what Shopify now pushes everyone to, including new stores: *"New stores can
  only use the latest version of customer accounts."* and *"As of February 26, 2026, legacy customer
  accounts are deprecated. They're no longer available to new stores, and existing stores that weren't
  using them no longer have access."*
  (<https://shopify.dev/docs/apps/build/customer-accounts.md>, "Product roadmap".)
* **UNVERIFIED:** no primary source was found stating "new customer accounts requires plan X" in either
  direction for Grow specifically. The absence of a plan-requirement aside on the manage page is the
  evidence, not an explicit statement.

**Customer Account API on Grow: available and plan-tiered by rate limit, with a documented 402.**

* The Customer Account API's requirements are stated as: *"You have **Apps and channels** permissions on
  the Shopify store that you're working with"* and *"You have installed the Headless or Hydrogen sales
  channel from the Shopify App Store."* **No plan requirement is listed.**
  (<https://shopify.dev/docs/storefronts/headless/building-with-the-customer-account-api/getting-started.md>,
  "Requirements".)
* The API reference publishes **per-plan rate limits**, which is direct evidence the API is meant for
  sub-Plus plans: **Standard limit: 100 points/second**, **Advanced Shopify limit: 200 points/second**,
  **Shopify Plus limit: 200 points/second**, **Shopify for enterprise (Commerce Components): 400
  points/second**; quota 7,500 cost points per app, per store and customer; per-customer limit 3,000
  requests/minute. (<https://shopify.dev/docs/api/customer/latest.md>, "Rate limits".)
  Shopify's current paid tier between "Standard/Basic" and "Plus" is named **Grow**; **UNVERIFIED** that
  "Advanced Shopify" in this list is the same plan as today's "Grow" — the docs do not use the word "Grow"
  anywhere on the Customer Account API pages.
* **The 402 behaviour the parent asked about exists and is documented for this API**, in the Customer
  Account API reference, both in prose and as a sample response:
  * `402 Payment Required` — *"The shop is frozen. The shop owner will need to pay the outstanding balance
    to unfreeze the shop."*
  * and, under "Sample error codes", `402` → `"errors": "This shop's plan does not have access to this
    feature"`.
  Source: <https://shopify.dev/docs/api/customer/latest.md> (HTTP status codes + sample error codes).
  Note the two statements are not perfectly consistent with each other, and neither names a plan.
* A related gate clause appears on the Admin API mutation for the checkout/accounts editor:
  *"Also: User must have `manage_checkout_settings` permission and **shop must have access to the checkout
  and accounts editor as well as the contextualized checkouts and customer accounts feature**."*
  (<https://shopify.dev/docs/api/admin-graphql/latest/mutations/checkoutAndAccountsConfigurationUpdate.md>).
  **UNVERIFIED** which plans satisfy that clause.
* Community, not documentation: a 2026-05-12 Shopify developer-forum thread has a participant describing
  *"We are implementing a B2B portal ... using **Shopify Grow and New Customer Accounts**"*
  (<https://community.shopify.dev/t/34164.json>). That is a forum user's setup, useful only as an
  indication that the combination is in use.

## 2.4 Legacy lifecycle: deprecation date and sunset date

**Deprecation date: February 26, 2026. Confirmed by three independent Shopify-owned sources.**

1. **Shopify Changelog** (changelog.shopify.com), post dated **February 26, 2026**, "Legacy customer
   accounts are deprecated": *"Legacy customer accounts are no longer available to new stores and existing
   stores not using it. Shopify will stop providing feature updates and technical support for this older
   version. **A final sunset date for legacy customer accounts will be announced later in 2026.**"*
   — <https://changelog.shopify.com/posts/legacy-customer-accounts-are-now-deprecated>
2. **`shopify.dev`, Building apps for customer accounts**, "Product roadmap": *"As of February 26, 2026,
   legacy customer accounts are deprecated. They're no longer available to new stores, and existing stores
   that weren't using them no longer have access. All merchants must upgrade to the latest version of
   customer accounts."* — <https://shopify.dev/docs/apps/build/customer-accounts.md>
3. **Shopify Developer Community announcement** by *"Ryan ... from the Customer Accounts team"*, posted
   **2026-02-26T15:22Z**, titled "Legacy customer accounts: Availability update"
   (<https://community.shopify.dev/t/legacy-customer-accounts-availability-update/31724>, readable as
   <https://community.shopify.dev/t/31724.json>): *"Today, legacy customer accounts are deprecated."* ...
   *"Starting February 2026, legacy customer accounts are no longer available to new stores and existing
   stores not using it. Shopify will stop providing feature updates and technical support for this older
   version."* ... *"**A sunset date for legacy customer accounts will be announced later in 2026.**"* ...
   *"Legacy customer account liquid templates (customers/account.liquid, customers/login.liquid,
   customers/register.liquid) will eventually be locked from editing, then removed."* ... *"The Customer
   Account API is the only primary source for customer-scoped data and authenticated customer actions. The
   Storefront API customer mutations will be deprecated, with more details coming soon."*

Also on the merchant-facing side, every customer-accounts help page now carries the caution: *"Legacy
customer accounts are deprecated. Upgrade to the latest version of customer accounts in your Shopify admin
to leverage more secure sign-in, no-code customizations with apps, and features such as store credit and
self-serve returns. **You can revert within 30 days.**"*
(<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>,
<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade/compare-features.md>).
The legacy settings page itself (`/manual/customers/customer-accounts/upgrade/legacy-customer-accounts`)
was checked repeatedly and **no longer resolves to a document** — bare URL 403s behind the bot challenge
and `.md` returns **404 (9 bytes, "Not Found")** — i.e. the legacy setup guide has been withdrawn from the
help centre.

**Sunset date: still unannounced as of 2026-10-13.** Both the changelog post and the developer-community
announcement say a **final** sunset date *"will be announced later in 2026"*, and **neither has been
updated with one** as of this note's date. No `shopify.dev` release note (checked `2026-10`, `2026-01`),
no `shopify.dev` changelog entry, and no help-centre page found states a sunset date. The developer-forum
announcement thread carries follow-up questions from merchants on the same day and no date
(<https://community.shopify.dev/t/31724.json>).

Corroborating community evidence that the announcement is the source of the "no sunset date yet" claim —
a 2026-02-27 Shopify Community post quotes *"A sunset date for legacy customer accounts will be announced
later in 2026"* and asks whether final migration will happen during 2026
(<https://community.shopify.com/t/590122.json>). In the same thread another merchant reports a store-side
message: *"You can revert to legacy customer accounts until March 25, 2026."* (community, unverified, and
store-specific). A 2026-03-23 developer-forum post points to the changelog post above
(<https://community.shopify.dev/t/32549.json>).

**UNVERIFIED and worth flagging:** whether a concrete sunset date has been announced by any channel
outside the three checked (help centre, `shopify.dev` changelog/release notes, both community forums). No
such date was found in any of them on 2026-10-13.

## 2.5 Does `shopify.com/<id>/account` mean no exposure to the legacy sunset?

**Merely strongly indicated — not certain.**

**What is certain (documented):**

* `shopify.com/<store-ID>/account` is the **new** customer accounts URL format, and its presence in
  **Settings > Customer accounts > URL** with a **Change domain** button is the documented UI for the new
  system's account domain
  (<https://help.shopify.com/en/manual/customers/customer-accounts/customize-customer-accounts/connect-domain-customer-account.md>).
* Legacy customer accounts are the **only** system being sunset; the new system is the migration target
  (<https://changelog.shopify.com/posts/legacy-customer-accounts-are-now-deprecated>).
* Legacy customisation artefacts are theme templates and legacy URL paths, which are **not** what that
  panel describes; new customer accounts is *"Managed independently from your theme"*
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>).
* The Admin GraphQL object backing that panel exposes `customerAccountsVersion` with an explicit
  `CLASSIC` / `NEW_CUSTOMER_ACCOUNTS` discriminator — the only machine-checkable answer
  (<https://shopify.dev/docs/api/admin-graphql/latest/enums/CustomerAccountsVersion.md>).

**Why it is not certain, in the docs' own words:**

* **The URL can be populated before the cutover.** Stores that are still on legacy accounts can configure
  and publish a new accounts experience, and set a subdomain, in advance: *"Your online store and checkout
  still link to legacy customer accounts until you complete Step 9."* The **URL** field is described as
  showing *"the current URL"* — during a migration that can be the not-yet-live new URL
  (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md>,
  <https://help.shopify.com/en/manual/customers/customer-accounts/customize-customer-accounts/connect-domain-customer-account.md>).
* **The definitive marker of a not-yet-cut-over store is the presence of an `Upgrade` banner**, and the
  URL field is explicitly one of the things you copy **before** upgrading: *"To test the new customer
  accounts experience before completing the upgrade, copy your new customer accounts URL..."*
  (same upgrade page, Steps 8 and 9). If a store can revert *"within 30 days"*, it must also be able to
  show this page while still serving legacy pages.
* **No primary source states "a shopify.com/<id>/account URL is only shown by stores already on new
  customer accounts."** The inference is from the two facts above plus the absence of an Upgrade-banner
  mention in the observed UI — **strongly indicated, not proven**.

**The two clean, documented checks to settle it (facts, not recommendations):**

1. Read **Settings > Customer accounts** for the **Upgrade** banner and button; its absence is the
   documented signal that Step 9 is done
   (<https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md#step-9>).
2. Query the Admin GraphQL field **`Shop.customerAccountsV2 { customerAccountsVersion }`** and read
   `NEW_CUSTOMER_ACCOUNTS` vs `CLASSIC`
   (<https://shopify.dev/docs/api/admin-graphql/latest/objects/CustomerAccountsV2.md>,
   <https://shopify.dev/docs/api/admin-graphql/latest/enums/CustomerAccountsVersion.md>).

---

## 3. Verification notes and gaps

**Method:** all `shopify.dev` and `help.shopify.com` pages cited above were fetched 2026-10-13 as raw
Markdown by appending `.md`; `help.shopify.com` bare URLs return 403 (bot challenge) and `.md` returns
200 — see [§0](#0-how-this-was-verified-and-one-method-finding-worth-reusing).

**Explicitly UNVERIFIED in this note:**

1. **Metafield values whose definition does not exist in the destination store.** The CSV page only
   promises columns for *defined* metafields. Whether an undefined metafield's value is exported,
   imported, or silently dropped is not documented anywhere found.
2. **What an *export* writes into `Option1 value`** for a one-variant product whose option name is `Title`
   (the merchant's exact shape). The docs and the official sample CSV disagree on naming — see §1.5.
   Only the merchant's own export file settles it.
3. **Export filename** (never named) and whether **"All products"** exports are always emailed
   (documented as emailed, no size threshold given).
4. **The import "review" screen's contents** — no doc calls it a preview, validation report, or dry run.
5. **Whether import processing continues after the admin tab closes**, and the exact progress surface
   (docs mention only a confirmation email and the activity log).
6. **Image fetch rate limits / concurrency caps** during import.
7. **`Inventory quantity` behaviour into a multi-location store** (docs only redirect to the inventory CSV
   / Inventory API).
8. **Whether a collections CSV export/import exists anywhere in the admin** — none is documented; the
   product CSV explicitly excludes the `Collection` column and caps import to one collection per product.
9. **`Published` vs `Published on online store`** column naming: the current docs and the official sample
   use `Published on online store`; the legacy header list published in the help centre's troubleshooting
   article uses `Published` and `Handle`/`Body (HTML)`/`Image Src`. Whether a current export ever writes
   the legacy names is not stated.
10. **Plan gating of new customer accounts** — no primary source says which plans may use it; only
    adjacent gates were found (Saved payment methods = Enterprise; Identity provider and Multipass = Plus).
11. **Whether "Advanced Shopify" in the Customer Account API rate-limit table = today's "Grow" plan.**
12. **Whether a legacy-accounts store can see a "Sign-in links" row** on the settings panel.
13. **Any sunset date for legacy customer accounts.** As of 2026-10-13 the only statement found is
    *"will be announced later in 2026"*.
14. **Metaobject definitions/entries travelling with a product CSV** — only reference identifiers are
    documented, which is not the same thing.

**Primary sources consulted (all Shopify-owned):**

| Source | URL |
| - | - |
| Exporting products | <https://help.shopify.com/en/manual/products/import-export/export-products.md> |
| Importing products with a CSV file | <https://help.shopify.com/en/manual/products/import-export/import-products.md> |
| Using CSV files to import and export products | <https://help.shopify.com/en/manual/products/import-export/using-csv.md> |
| Solutions to common product CSV import problems | <https://help.shopify.com/en/manual/products/import-export/common-import-issues.md> |
| Official sample product CSV | <https://help.shopify.com/csv/product_template.csv> |
| Metafields (merchant) | <https://help.shopify.com/en/manual/custom-data/metafields.md> |
| Metafield definitions | <https://help.shopify.com/en/manual/custom-data/metafields/metafield-definitions.md> |
| Editing metafields in bulk | <https://help.shopify.com/en/manual/custom-data/metafields/bulk-edit-metafields.md> |
| Metafields (developer) | <https://shopify.dev/docs/apps/build/metafields> |
| Collections | <https://help.shopify.com/en/manual/products/collections.md> |
| Customer accounts (help) | <https://help.shopify.com/en/manual/customers/customer-accounts.md> |
| Setting up and managing customer accounts | <https://help.shopify.com/en/manual/customers/customer-accounts/manage.md> |
| Upgrading to customer accounts from legacy | <https://help.shopify.com/en/manual/customers/customer-accounts/upgrade.md> |
| Customer accounts vs legacy (comparison) | <https://help.shopify.com/en/manual/customers/customer-accounts/upgrade/compare-features.md> |
| Connecting a customer accounts subdomain | <https://help.shopify.com/en/manual/customers/customer-accounts/customize-customer-accounts/connect-domain-customer-account.md> |
| Identity provider (Plus gate) | <https://help.shopify.com/en/manual/customers/customer-accounts/sign-in-options/identity-provider.md> |
| `shopify.dev` — Building apps for customer accounts | <https://shopify.dev/docs/apps/build/customer-accounts.md> |
| Customer Account API getting started | <https://shopify.dev/docs/storefronts/headless/building-with-the-customer-account-api/getting-started.md> |
| Customer Account API reference (rate limits, 402) | <https://shopify.dev/docs/api/customer/latest.md> |
| `Shop.customerAccountsV2` | <https://shopify.dev/docs/api/admin-graphql/latest/objects/CustomerAccountsV2.md> |
| `CustomerAccountsVersion` enum | <https://shopify.dev/docs/api/admin-graphql/latest/enums/CustomerAccountsVersion.md> |
| `checkoutAndAccountsConfigurationUpdate` | <https://shopify.dev/docs/api/admin-graphql/latest/mutations/checkoutAndAccountsConfigurationUpdate.md> |
| Shopify Changelog — legacy accounts deprecated | <https://changelog.shopify.com/posts/legacy-customer-accounts-are-now-deprecated> |
| Developer community announcement (2026-02-26) | <https://community.shopify.dev/t/legacy-customer-accounts-availability-update/31724> |

**Community sources used only as labelled corroboration (never as sole support):**
<https://community.shopify.dev/t/34164.json> (Grow + new customer accounts, forum user),
<https://community.shopify.com/t/590122.json> (sunset-date question, 2026-02-27),
<https://community.shopify.com/t/214856.json> (staff-authored forum article on `Title`/`Default Title`),
<https://community.shopify.com/t/396027.json> (vendor-affiliated report of silent image loss),
<https://community.shopify.dev/t/32549.json> (points at the changelog post),
<https://community.shopify.com/t/686939.json> (category-metafield columns, 2026-09-24).