Upgrading PHP version on Linux for Apache

1. Install the Apache module for specific php version

   sudo apt install libapache2-mod-php7.3
   

2. Copy the php.ini from previous version to newer version after making a backup of the original php.ini for new version.

   sudo cp /etc/php/7.3/apache2/php.ini php.ini.original
   sudo cp /etc/php/7.2/apache2/php.ini /etc/php/7.3/apache2/php.ini
   

3. Install specific php modules for Apache and enable the php modules on new version of php.

   sudo apt install php7.3-curl php7.3-gd php7.3-gmp php7.3-intl php7.3-mbstring php7.3-simplexml php7.3-soap php7.3-wddx php7.3-xmlreader php7.3-xmlrpc php7.3-xmlwriter php7.3-xsl php7.3-zip php7.3-xml php7.3-mysql
   sudo phpenmod -v 7.3 pdo_mysql soap wddx xmlreader xmlrpc xsl zip intl gd dom curl mysqlnd gmp simplexml mysqli mbstring
   

4. Disable old php version, enable new version and restart Apache server.

   sudo a2dismod php7.2
   sudo a2enmod php7.3
   sudo systemctl restart apache2