Upgrade PHP version 7.2 to 7.3 on Ubuntu

As a part of increasing the security, it is advised to keep your PHP version up to date. Here we have provided the steps to upgrade the current PHP 7.2 version to 7.3 on Ubuntu 14/16/18 versions without removing the old one. So that we can revert to the older versions if something incompatible with the new one after switching.

Login to the server via SSH as root.

Check your current PHP version. 

# php -v
PHP 7.2.36

In order to install PHP 7.3, we need to add the repository first:

# add-apt-repository ppa:ondrej/php

Then run an update:

# apt-get update

After completing the update, we need to install the PHP 7.3.

 Then install the required PHP packages based on your current installation:

# apt install php7.3-common php7.3-cli php7.3-bz2 php7.3-curl php7.3-gd php7.3-intl php7.3-json php7.3-readline php7.3-xml php7.3-zip php7.3-fpm php7.3-bcmath php7.3-mbstring

After a successful installation, we can disable the old 7.2 and then enable 7.3:

# a2dismod php7.2
# a2enmod php7.3

Then restart Apache:

# service apache2 restart

The new PHP version should be active now. You can verify it from the command line:

# php -v
PHP 7.3.28

NOTE: for ordinary user use sudo command.