Update: Install Multiple PHP Versions on Ubuntu 16.04

In this article, we will be discussing how to install Multiple PHP Versions on Ubuntu 16.04. Ubuntu 16.04 LTS servers assign the PHP 7.0 version by default. Although PHP 5.6 is currently EOL (end of life) as of December of 2018, some applications may not be compatible with PHP 7.0. For this tutorial, we instruct on how to switch between PHP 7.0 and PHP 5.6 for Apache and the overall default PHP version for Ubuntu.

Install PHP 5.6

Step 1: Update Apt-Get

As always, we update and upgrade our package manager before beginning installation. If you are currently running PHP 7.X, after updating apt-get, continue to step 2 to downgrade to PHP 5.6.

apt-get update && apt-get upgrade

Step 2: Install PHP 5.6
Install the PHP5.6 repository with these two commands.

apt-get install -y software-properties-common
add-apt-repository ppa:ondrej/php
apt-get update
apt-get install -y php5.6

PHP Version for Apache

Step 3: Switch PHP 7.0 to PHP 5.6
Switch from PHP 7.0 to PHP 5.6 while restarting Apache to recognize the change:

a2dismod php7.0 ; a2enmod php5.6 ; service apache2 restart

Now, let’s verify that PHP 5.6 is running on Apache by creating a PHP info page. To do so, insert the code below into a file named  phpinfo.php and upload it to the /var/www/html directory.

<? phpinfo(); ?>

By visiting http://xxx.xxx.xxx.xxx/phpinfo.php (replacing the x’s with your server’s IP address), you’ll see a PHP info banner similar to this one, confirming the PHP Version for Apache:

Continue onto the section PHP Version for Ubuntu to edit the PHP binary from the command line.

PHP Version for Ubuntu

Step 4: Edit PHP Binary

Maintenance of symbolic links or the /etc/alternatives path through the update-alternatives command.

update-alternatives --config php

Output:
There are 2 choices for the alternative php (providing /usr/bin/php).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/php7.0 70 auto mode
1 /usr/bin/php5.6 56 manual mode
2 /usr/bin/php7.0 70 manual mode
Press to keep the current choice[*], or type selection number:

Select php5.6 version to be set as default, in this case, its the number one option.

You can now verify that PHP 5.6 is the default by running:
php -v

Output:
PHP 5.6.37-1+ubuntu16.04.1+deb.sury.org+1 (cli)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies