How can version differences between PHP installations affect variable usage on different servers?

Version differences between PHP installations can affect variable usage on different servers because certain variable declarations or functions may not be supported in older versions of PHP. To ensure compatibility across different servers, it is important to check the PHP version before using certain features and provide alternative implementations if necessary. 

if (version_compare(PHP_VERSION, '7.0.0') >= 0) {
    // Use newer PHP features
    $newVariable = 'New variable';
} else {
    // Fallback for older PHP versions
    $oldVariable = 'Old variable';
}

Keywords

PHP version differences variable usage server compatibility backward compatibility PHP functions

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