If you got a Hotel Booking plugin built into rental theme (e.g. Villagio, Campterra, Alpenhouse, Petotel... full list) you may get new version of plugin just after theme update. Thus you need to keep your theme updated in order to get latest version of Hotel Booking plugin. Once you update theme you should navigate to Dashboard > Appearance > Install Plugins and check if there are available updates for integrated plugins.
Note: it is possible to purchase Hotel Booking license apart from theme in order to control plugin updates on your own.