# PrestaShop 1.7.0 to 1.7.8: the only 1.7 that runs PHP 7.4

> Staying on 1.7.0 while your host drops PHP 7.1, 7.2 or 7.3 breaks the shop outright: only 1.7.8 supports PHP 7.4 within the 1.7 branch.

- Source canonique : [https://allaux.fr/en/prestashop/migration/1-7-0-vers-1-7-8](https://allaux.fr/en/prestashop/migration/1-7-0-vers-1-7-8)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## Direct answer

> Stay inside the 1.7 branch but go all the way to 1.7.8, the only sub-version that accepts PHP 7.4. Do the PrestaShop update first, with the old PHP version still active at the host, and switch PHP only once the shop is back up: the reverse order takes the site down for the whole job.

## Signs this is the migration you need

- Your host announces the end of PHP 7.1, 7.2 or 7.3 support soon and only offers PHP 7.4 or higher.
- After a host-forced PHP change, the back office or front end throws a Smarty-related fatal error without any module having been touched.
- Your shop is still on 1.7.0, 1.7.1 or an earlier sub-version than 1.7.5, and you don’t know how far it can go on PHP without changing sub-version.
- A provider or host has suggested jumping straight to PHP 8 without changing PrestaShop version to fix a hosting issue.

## What this move actually changes inside the 1.7 branch

Unlike a jump to 8 or 9, migrating from 1.7.0 to 1.7.8 stays within the same major branch: architecture, theme and database structure don’t change. The real issue is PHP compatibility. Sub-versions 1.7.5 to 1.7.8 are the only ones supporting PHP 7.2; only 1.7.8 supports PHP 7.4. A shop still on 1.7.0 to 1.7.4 doesn’t run under PHP 7.4: not incompatible modules, it’s PrestaShop’s core itself that isn’t built for that PHP version.

That becomes concrete when a host removes older PHP versions, as 7.1, 7.2 and 7.3 fall out of upstream maintenance. If the shop isn’t at least on 1.7.8 when the host cuts pre-7.4 versions, it stops starting.

One thing needs to be clear: moving to 1.7.8 only fixes this temporarily. No 1.7 sub-version, not even 1.7.8, runs under PHP 8. The 1.7.8.x line went into security-only maintenance after PrestaShop 8 shipped, and that phase ended when PrestaShop 9 arrived: no longer covered at all. 1.7.8 is a stopover towards PHP 7.4, not a lasting fix.

## How I handle this minor update

1. **Checking the exact sub-version** — I check the shop’s exact 1.7 sub-version and the current and target PHP version with the host, to know how far it needs to go.
2. **Full backup** — SQL dump and full file copy before anything, even for a minor update: lower risk than a major jump, but not zero.
3. **Updating via the autoupgrade module** — I bring the shop up to 1.7.8 with autoupgrade, which handles minor updates like this one as well as major version jumps.
4. **Testing on a copy when the timeline allows** — When the deadline allows, I test the update on a copy first; otherwise I work outside peak hours. I also check that modules declare compatibility covering 1.7.8, since some publishers froze their declaration on an earlier sub-version without an actual code problem.
5. **Planning what comes next** — Once 1.7.8 is stable on PHP 7.4, I plan the real migration with you, to PrestaShop 8, the only way to get PHP 8 compatibility.

## 1.7.8 isn’t a long-term fix

> Even fully updated, 1.7.8 doesn’t run on PHP 8 and hasn’t been covered by security maintenance since PrestaShop 9. It’s an intermediate step that unblocks hosting now, not a destination.

## How I check nothing was lost

Even on a minor update, I compare order, customer and product volumes before and after, to make sure autoupgrade didn’t leave anything behind. I test checkout and main pages under the new PHP version, and watch the PHP error log over following days, to spot a module that worked on the old sub-version but chokes under PHP 7.4.

## Related pages

- **Moving PrestaShop to PHP 8** — What the PHP version change involves, once 1.7.8 is reached. ([/prestashop/migration/passer-a-php-8](/prestashop/migration/passer-a-php-8))
- **PrestaShop migration from 1.7 to 8** — The real migration to plan once stable on 1.7.8, to get past the PHP 7.4 ceiling. ([/prestashop/migration/1-7-vers-8](/prestashop/migration/1-7-vers-8))
- **Checklist before a migration** — What to check and back up before any update, even a minor one. ([/prestashop/migration/checklist-avant-migration](/prestashop/migration/checklist-avant-migration))
- **Changing host while migrating PrestaShop** — If your host is dropping PHP 7, a chance to weigh up a hosting change too. ([/prestashop/migration/changer-d-hebergeur](/prestashop/migration/changer-d-hebergeur))

## FAQ

### Why does my site suddenly break when I haven’t changed anything on the shop?

Because your host changed something: it removed older PHP versions. If your shop stayed on 1.7.0 to 1.7.5, it was never built for PHP 7.4; only 1.7.8 supports that within the 1.7 branch.

### Does moving to 1.7.8 protect me long term?

No. 1.7.8 unblocks PHP 7.4, but no 1.7 sub-version runs under PHP 8, and the line hasn’t been maintained since PrestaShop 9. It’s a stopover, not a destination: plan the migration to 8 straight after.

### Can I move to PHP 8 directly without changing PrestaShop version?

No, that doesn’t work: no 1.7.x version runs under PHP 8, Smarty crashes immediately. You need to migrate to PrestaShop 8 first.

### Will this update change how my shop looks?

No, within the 1.7 branch the Classic theme and how it works don’t change. This update touches neither design nor URL structure.