• First and foremost, let check your PHP version in your local machine (Assumption that we are using Windows).

php -v

• The next step, run php --ini to check php.ini location:

php --ini

Example output:

php -v
PHP 8.0.6 (cli) (built: May  4 2021 23:31:45) ( ZTS Visual C++ 2019 x64 )
Copyright (c) The PHP Group
Zend Engine v4.0.6, Copyright (c) Zend Technologies

php --ini
Configuration File (php.ini) Path:
Loaded Configuration File:         C:\xampp\php\php.ini
Scan for additional .ini files in: (none)
Additional .ini files parsed:      (none)

• Assume that we want to upgrade the PHP version for XAMPP. Let's attempt to download a specific version from here: https://sourceforge.net/projects/xampp/files/XAMPP%20Windows/7.3.30/.

• Change the Apache and PHP folders by adding '.old' to create backups that can be rolled back to the old version in XAMPP.

• After that, copy the Apache and PHP folders from the upgraded XAMPP to the old location of XAMPP on the local machine.

• Use Ctrl + F to search for '\xampp' in php.ini and make changes to the following lines.

include_path = C:\xampp\php\PEAR
extension_dir = "C:\xampp\php\ext"
```"