PrestaShop error 500 or blank screen: what to do right now
Your PrestaShop shop shows error 500 or a blank page: what to do now without making it worse, how to see the real error…
Is it worth it to upgrade PrestaShop 1.7 to 9, or to migrate PrestaShop 1.6 to 9? If your shop is still selling but every time the bank changes something in card payments you have to call someone to patch it up, yes. The migration is done without closing your shop, you keep your products, customers, orders and Google rankings, and a small shop costs from €690.
Here it is without the jargon: what happens if you don't upgrade, what you take with you to the new version, what changes, and how long it takes and what it costs.
Working today doesn't mean it will keep working. A PrestaShop 1.6 or 1.7 shop falls behind on three fronts at once.
PrestaShop relies on PHP, the language it's written in, which runs on your server. Versions 1.6 and 1.7 only work with old PHP versions that no longer get security patches. PrestaShop 9 runs on PHP 8, which does. Every month on an unpatched PHP makes your shop an easier target, and your customers' data is in there.
Payment gateways and carriers maintain their modules for current versions. The day they change something on their side, the old module stops working and you find yourself unable to take payments or print shipping labels. You don't get to pick that day.
The current version loads faster and works better on mobile, which is where almost everyone buys from you. Google notices, and so do your customers.
The question usually isn't whether to upgrade, but whether you'd rather do it when you decide or when something breaks.
No, if it's done right. In a migration from PrestaShop 1.6 or 1.7 to PrestaShop 9, the new version is installed from scratch on an up-to-date server, and then everything that's yours is moved over:
A redirect (techies call it a "301") is a permanent notice: "this page lives here now". Google follows it, passes what it already knew about the old page on to the new one, and your customer lands where they should instead of on an error. It's what decides whether you keep your rankings or start from zero.
No. The new shop is built on a copy while yours keeps selling. You check it with your real data and, on switchover day, the latest orders are moved across and your domain is pointed to the new shop.
Yes. There's no need to go through 1.7 or 8. Installing the current version from scratch and moving your data over is cleaner than upgrading one version at a time, and it doesn't drag along leftovers from old installations.
The same goes if you're coming from 1.7: the path is the same.
This is where most surprises happen, so it's better to know beforehand.
Themes from 1.6 and 1.7 don't work on the new version. It's not a matter of tweaking them: you need a current one. A modern theme is installed with your logo, your colours and your photos, so your shop still looks like yours. If you'd like to take the chance to launch a custom design, that's possible too.
Each module moves to its current version or to an equivalent one. Some don't exist for PrestaShop 9: in that case you're told before work starts, with the alternative and its price. No finding out on switchover day.
If someone built something special for your shop, it has to be rebuilt for the new version. It's checked beforehand and included in the quote, so you know what it costs from the start.
For a small shop, about 15 working days from the moment you give the go-ahead. For larger shops, the date comes with the fixed price.
The process has four steps:
A complete migration costs from €690 for a shop with fewer than 1,000 products, few third-party modules and no custom development. That price includes:
Whatever adds real work: a catalogue of more than 1,000 products, more than 10 third-party modules, a blog to move over, more than 5 pages of your own, or custom features. Each one adds a few hours, and in the wizard you can see how the price changes as you tick it.
If your shop is large or has a lot of custom work, we'll give you a fixed price within 24 hours.
These are October 2026 rates and an estimate: depending on what your shop needs, the price may vary slightly. You'll have yours, fixed, before work starts.
If your shop sells and you want it to still be selling a year from now, yes. Upgrading calmly, with a test copy and a fixed price, costs less than doing it in a rush the day card payments break.
Want to know how much it would cost to move your shop to PrestaShop 9? Answer a few questions about your shop and see the price in a minute.
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A module, an app, a server that is giving you trouble or something urgent. We answer within 24 hours, with a fixed quote with a price and a date.