Every component runs in your shop with one of two frontend engines: Legacy, the proven configurator, or V3, the new engine. Both read the same data – characteristics, values, prices and rules. But they display it differently, and some functions exist in only one of them. This article shows where each engine runs, how they differ and how to switch safely.
Where you set the engine
You set the engine per component:
- Open the component and switch to the Settings tab on the left.
- In the General tab, at the very bottom, you find Frontend engine with the field Engine.
- Choose Legacy (default) or V3.
- Save and publish the component. Only then does the new engine apply in your shop.
The setting does not change:
- your data – characteristics, values, prices, rules and tables stay as they are,
- the editor in the admin – you edit the component exactly as before,
- publishing – the check and the process are the same for both engines.
So you can switch back at any time.
Which engine runs where
Not every integration follows the setting:
| Where the component runs | Engine |
|---|---|
| Preview in the admin | The engine you set. This lets you test a switch before your customers see it. |
| Magento 2 | The engine you set. Components with Legacy and with V3 run side by side in the same shop. |
| Shopify | Always V3, regardless of the setting. |
| PrestaShop 8.1 / 9 | Always V3, regardless of the setting. |
| Shopware 6 | From version 5.2.0 of the plugin the engine you set, as in Magento 2. With the plugin setting Configurator version you can instead fix Always V3 or Always the previous version for the whole shop. Older plugin versions always load Legacy. |
| HTML snippet | The snippet decides, not the setting: the classic snippet of the HTML5 card loads Legacy, the snippet of the HTML5 (V3) card loads V3. |
Accounts without the classic cloud run with V3 wherever the engine depends on the account – the setting Legacy (default) has no effect there. You recognise such accounts by this note under Settings → Integrations: "Shop plugins connect through the service portal — no security token is needed here."
More on the individual integrations: Install Magento Plugin, Install Shopware Plugin, Installing the Shopify Plugin, Installing the PrestaShop Plugin, HTML Snippet Integration.
What differs
V3 only
| Function | What Legacy does instead |
|---|---|
| Captcha (data type Captcha (V3 only), protects the action button against spam) | Cannot display it – see The "V3" badge |
Combined product image in PDF and email (placeholder {{combined_image}} in the action button) |
The placeholder stays empty |
| Rule weighting (the Weight field in the rule settings determines the order) | Ignores the weight; rules run in their saved order |
Conditions in tiered pricing (>=, >, =, <=, <, !=) |
Ignores the condition and always takes the highest tier whose value is less than or equal to the input; if the input is below all tiers, the smallest tier applies |
Formulas with characteristic names without $ (width * height) and round(x, 2) with decimal places |
Needs $width; whether round is known depends on the shop page |
| Showing characteristics hidden by rules as disabled (setting Values excluded by rules = Show disabled) | Shows only excluded values as disabled; hidden characteristics disappear |
Legacy only
| Function | What V3 does instead |
|---|---|
| Accordion display | Shows the characteristics without group navigation (like No groups) |
| 3D icon, turning by click and automatic rotation in the 360° view | Turns the 360° view by dragging or with the arrow keys, without these extras |
| Autocomplete (selection as a search field) | Shows a normal selection list with all values |
| Date field with calendar and restrictions (e.g. Allow past days) | Shows a plain text field without a calendar |
| Predefined qty and Predefined min/max (rule types) | Skips these rules |
Multi-line formulas with var, if or for |
Evaluates only one expression; multi-line formulas return no result. Write conditions as condition ? a : b. |
More on formulas: Formulas & Calculations. More on tiered pricing: Set Up Pricing.
The "V3" badge
Some characteristics need V3 – currently that is the Captcha. If a component contains such a characteristic,
- it carries the badge V3 in the component overview,
- the component settings show the note Requires Frontend V3,
- Magento 2 and Shopware 6 (from plugin version 5.2.0) load it with V3 automatically – even if Engine still says Legacy (default).
This does not block publishing. Integrations that only load Legacy – the classic HTML5 snippet and the Shopware plugin before version 5.2.0 – cannot display such a component correctly, though. Do not use a Captcha there.
So the badge does not tell you which engine you set, but that the component does not fully work without V3.
Which engine should you use?
Stay with Legacy (default) if
- your component is already live and works as it should,
- you use Accordion, Autocomplete, date fields, predefined quantities or min/max, or multi-line formulas,
- your shop runs on Shopware 6 with a plugin version before 5.2.0.
Choose V3 if
- you are building a new component and need none of the Legacy functions above,
- you want to use Captcha, the combined product image in the PDF or rule weighting,
- your shop runs on Shopify or PrestaShop – V3 runs there anyway.
Switching an existing component
- Set Engine to V3 and save – do not publish yet.
- Check in the preview: do all characteristics appear? Is the price right for a few typical configurations?
- Pay special attention to tiered pricing: if a tier has a condition other than
>=, V3 calculates differently than before. A tier ">10" applies from 11 in V3, but already from 10 in Legacy. - Check formulas: rewrite multi-line formulas as a single expression first.
- If everything fits, publish. If you do not like the result, simply set it back to Legacy (default) and publish again.
Troubleshooting
- The switch has no effect in the shop – the engine only applies after publishing. Also check the table above: Shopify and PrestaShop always run V3, Shopware 6 follows the setting only from plugin version 5.2.0 (check its Configurator version too), and with the HTML snippet the snippet decides.
- A characteristic is missing or looks different – the component uses a function the chosen engine does not know. For characteristics it does not know at all, V3 shows the note "Unknown characteristic type". Compare with the tables above.
- The price differs after the switch – usually a tiered price with a condition other than
>=, or a formula that returns no result in one engine. Test the affected configuration in the preview with both engines. - A formula returns no result in V3 – it consists of several statements (
var,if,;). Write it as a single expression, e.g.$width > 200 ? $width * 1.2 : $width. - The component has the V3 badge although Legacy is set – it contains a Captcha. That is why it runs with V3 in Magento 2 and Shopware 6 (from plugin version 5.2.0); in the classic HTML5 snippet it does not fully work.