What are potential reasons for a new PHP installation not overriding an existing version?

The new PHP installation may not be overriding an existing version due to the PATH environment variable pointing to the old version, or the new PHP installation may not have been properly configured or installed. To solve this issue, update the PATH variable to point to the directory where the new PHP installation is located, or reinstall the new PHP version ensuring all necessary configurations are set correctly.

// Example code to update the PATH variable in PHP
putenv("PATH=/path/to/new/php/bin:" . getenv("PATH"));