public static function start()
    {
        $compatibility = [
            self::SUBSITES => null,
        ];

        if (ClassInfo::exists(Subsite::class)) {
            $compatibility[self::SUBSITES] = Subsite::$disable_subsite_filter;
            Subsite::disable_subsite_filter(true);
        }

        return $compatibility;
    }
public static function start()
    {
        $compatibility = [
            self::SUBSITES => null,
        ];

        if (ClassInfo::exists(Subsite::class)) {
            $compatibility[self::SUBSITES] = Subsite::$disable_subsite_filter;
            Subsite::disable_subsite_filter(true);
        }

        return $compatibility;
    }
Returns the state of other modules before compatibility mode is started.

@return array