update.php

<?php
function set_is_update() {

	$fv  = $this -> get_file_version();
	$dbv = $this -> get_database_version();

	// returns -1 if the first version is lower than the second, 0 if they are equal, and 1 if the second is lower.
	$compare = version_compare( $fv, $dbv );

	if( $compare === 1 ) {
		$out = TRUE;
		$this -> update_database_version( $fv );
	} else {
		$out = FALSE;
	}
		
	$this -> is_update = $out;

}