Hello. What is the version you have now? Up left on vmix screen it says Vmix and the version type. There exist 4 vmix versions lifetime buy with 1 year free upgrades and then 60$ per year as optional and one per month subscription. By the term "guests" you mean vmix call or zoom call? https://www.vmix.com/purchase/#comparisontable see this comparison table. For 1 guest per vmix preset/show vmix call or zoom call you can buy Vmix HD. For 2 until 4 vmix call or "unlimited" (depends on your internet bandwidth,etc) zoom guests you have to buy vmix 4k. For 5 to 8 vmix calls you have to buy vmix pro