Ubuntu 16.04服务器上为Magento 2将PHP7.2降级至7.0的方法求助

Hey there, let's get your PHP version downgraded from 7.2 to 7.0 on Ubuntu 16.04 for Magento (including Magento 2) — I've walked through this a few times, so here's a step-by-step that should work reliably:

1. Completely Uninstall PHP 7.2 #

First, we need to wipe out all traces of PHP 7.2 to avoid version conflicts later:

• Stop your web server first (adjust for Apache or Nginx):

  # For Apache
  sudo systemctl stop apache2
  
  # For Nginx
  sudo systemctl stop nginx
  

• Purge PHP 7.2 packages and leftover dependencies:

  sudo apt-get purge php7.2*
  sudo apt-get autoremove
  sudo apt-get autoclean
  

• Verify no PHP 7.2 packages remain (remove any stragglers if they show up):

  dpkg -l | grep php
  

2. Add PHP 7.0 Repository #

Ubuntu 16.04's default repos include PHP 7.0, but using a trusted PPA ensures we get stable, maintained packages:

sudo add-apt-repository ppa:ondrej/php
sudo apt-get update

This PPA is widely used for maintaining legacy PHP versions, so it's a safe bet for our downgrade.

3. Install PHP 7.0 & Magento-Required Extensions #

Magento (especially Magento 2) relies on specific PHP extensions to function properly. Install them alongside PHP 7.0:

• For Apache (using mod_php):

  sudo apt-get install php7.0 php7.0-cli libapache2-mod-php7.0 php7.0-mysql php7.0-curl php7.0-gd php7.0-intl php7.0-mbstring php7.0-xml php7.0-zip php7.0-soap
  

• For Nginx (using PHP-FPM):

  sudo apt-get install php7.0 php7.0-cli php7.0-fpm php7.0-mysql php7.0-curl php7.0-gd php7.0-intl php7.0-mbstring php7.0-xml php7.0-zip php7.0-soap
  

4. Set PHP 7.0 as the Default Version #

If any other PHP versions are still installed, switch the system default to 7.0:

sudo update-alternatives --set php /usr/bin/php7.0

Verify the change with:

php -v

You should see output starting with PHP 7.0.x if everything worked.

5. Reconfigure Your Web Server #

• For Apache:
  Disable the old PHP 7.2 module, enable PHP 7.0, then restart Apache to apply changes:

  sudo a2dismod php7.2
  sudo a2enmod php7.0
  sudo systemctl restart apache2
  

• For Nginx:
  Open your site's Nginx configuration file (usually in /etc/nginx/sites-available/) and update the fastcgi_pass line to point to PHP 7.0-FPM:

  fastcgi_pass unix:/run/php/php7.0-fpm.sock;
  

  Save the file and restart Nginx:

  sudo systemctl restart nginx
  

6. Verify Web Server PHP Version #

Create a temporary info file to confirm the web server is using PHP 7.0:

echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php

Visit http://your-server-ip/info.php in a browser — you should see PHP 7.0 listed at the top. Don't forget to delete this file afterward for security:

sudo rm /var/www/html/info.php

Quick Tips #

• Double-check that all Magento-required extensions are enabled (use php -m or the info.php page to confirm). Missing extensions will cause Magento installation or runtime errors.
• If you hit package conflicts, run sudo apt-get -f install to resolve dependency issues.

内容的提问来源于stack exchange，提问作者Gopi Nathan