In this tutorial I’ll show you how to upgrade PHP 5.6.xx which is by default installed by Vesta CP during installation to PHP 7.3.xx latest, I’ve tested on many server before writing this tutorial and its just working fine without any issue hence it is safe to upgrade to PHP 7.3 please be sure your script is compatible with php 7.3, part of this tutorial is copied from remi repository.

Why upgrade to php 7.3 –  Because it will give you security & performance boost + KICK, since WordPress will load much faster and uses less resources. And php 7.3 is 5% faster than any other previous version.

Upgrade to php 7.4 : https://blog.alphagnu.com/how-to-install-upgrade-to-php-7-4-on-rhel-centos-vestacp/

STEP 1 :

Install Remi Repository and EPEL Repository on your server :

RHEL 7

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
wget http://rpms.remirepo.net/enterprise/remi-release-7.rpm
rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm
subscription-manager repos --enable=rhel-7-server-optional-rpms

RHEL 6

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
wget http://rpms.remirepo.net/enterprise/remi-release-6.rpm
rpm -Uvh remi-release-6.rpm epel-release-latest-6.noarch.rpm
rhn-channel --add --channel=rhel-$(uname -i)-server-optional-6

CentOS 7

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
wget http://rpms.remirepo.net/enterprise/remi-release-7.rpm
rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm

CentOS 6

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
wget http://rpms.remirepo.net/enterprise/remi-release-6.rpm
rpm -Uvh remi-release-6.rpm epel-release-latest-6.noarch.rpm

STEP 2 :

After you have installed repository you need to follow some extra configurations :

Run this command one by one for RHEL or CentOS

yum install yum-utils
yum-config-manager --enable remi-php73

 STEP 3 :

Now just run this command :

yum update -y

You’ll see php packages are getting updated, After the update process you need to restart Apache server/php-fpm-(nginx) and check the php version from by below mentioned command:

php -v

[root@server ~]# php -v
PHP 7.3.0 (cli) (built: Dec  4 2018 16:12:20) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.0-dev, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.3.0, Copyright (c) 1999-2018, by Zend Technologies

Troubleshoot

If php upgrade process fails (no update/nothing happens) or you upgraded previously from 5.6 to 7.0/7.1/7.2 then you need to run this commands to disable php 5.6/7.0/7.1/7.2 :

yum-config-manager --disable remi-php56
yum-config-manager --disable remi-php70
yum-config-manager --disable remi-php71
yum-config-manager --disable remi-php72

After that follow the tutorial from STEP 2 again.