/**
* Use PHP's version_compare() to check the version
* of WordPress (or a plugin or theme for that matter).
*
* Get currently installed version of WP either using
* get_bloginfo( 'version' ) OR use the global $wp_version.
* Either is OK.
*/
global $wp_version;
// alternate method
// $wp_version = get_bloginfo( 'version' )
if ( version_compare( $wp_version, '5.0', '>=' ) ) {
echo "WordPress is at or above 5.0";
} else {
echo "WordPress version is below 5.0";
}