public static function getSolrMajorVersion() {
        $type = static::getSolrType();
        $version = FALSE;
        if ($type) {
            list(, $version) = explode(":", $type);
            if (preg_match('/^(\d)\./', $version, $matches)) {
                $version = $matches[1];
            }
            else {
                $version = '4';
            }
            // Platform support 3,4 and 6 atm. We only support 4 and 6.
            if ($version === '3') {
                $version = '4';
            }
        }
        return $version;
    }