# Switching PHP versions

> What the PHP version means and how to change it safely.

Source: https://veldhost.eu/docs/php-versions

PHP is the engine your site runs on. New versions are faster and safer; old code sometimes needs the version it was written for.

## Switching

Site → **PHP** tab → pick a version → apply. It takes effect within a minute, and you can switch back just as easily.

## Which version?

- **New project / up-to-date WordPress:** the newest offered.
- **Older app that breaks on the newest:** step down one version at a time until it runs, then plan an update — old PHP versions eventually lose security support.

## If the site errors after switching

Check the [Logs tab](https://veldhost.eu/docs/site-logs) — a fatal mentioning *deprecated* or *undefined function* right after a switch means some code isn't ready for that version. Switch back and update the code or plugin first.