public function checkPhpVersion()
    {
        $min = $this->getDependencyPhpVersionMin();
        $max = $this->getDependencyPhpVersionMax();

        $minOk = $min? version_compare(PHP_VERSION, $min, ">=") : true;
        $maxOk = $max? version_compare(PHP_VERSION, $max, "<=") : true;

        if(!$minOk || !$maxOk) {
            $err = "requires PHP version ";
            if($min && $max) {
                $err .= " >= $min and <= $max ";
            } elseif($min) {
                $err .= " >= $min ";
            } elseif($max) {
                $err .=  " <= $max ";
            }
            $err .= " current is: ".PHP_VERSION;
            return $err;
        }
        return true;
    }