If you’re using one those plugins you might stumble uppon a notice in Dashboard about need of providing purchase key.
Revolution Slider is included in theme on extended/developers license, which means we bought it for a higher price to be able to include it in our theme. You as end user can use it only with this theme, and do not get the license key that is used to auto-updates.
Updates of this plugin come with the updates of the theme (We always include latest Revolution Slider version in theme few days after release). You can of course buy own license if you want it faster or need support from plugin authors, but that’s not necessary.