By default a new instance of RapidDeploy does not come with the latest version of the plugins already installed. If you have a direct internet connection and need to update the plugins for any reason the easiest way to do this is via the Plugin Manager when you are logged into RapidDeploy.
Log in to RapidDeploy and go to:
System -> Plugin Manager -> Available Plugins Tab
If your RapidDeploy instance does not have an internet connection you can download the RTC plugin here