Starting from v5.0.0, there are a new OUTPUT elements called vDIGITAL, vTIMER and vCOUNTER. They have a exactly the same functionalities as DIGITAL, TIMER and COUNTER components, but the main difference is that these elements does not represent real(psychical) board pins.
When these components are usable?
Let's say that you have a temperature and moisture sensor, and you want to turn on the water pump for a certain time frame(pump relay is connected to the pin represented by TIMER component) when the temperature and moisture values are in (or out) of the required limits.
Before v5.0.0, for OUTPUTS, you will have to add one TIMER component, and one DIGITAL component which is used for EN (enable TIMER). DIGITAL component will have the RULE and it will change state from LOW to HIGH when the sensor values are in (or out) of the limits, and, as EN (enable) pin for TIMER, it will trigger the TIMER and the water pump.
Basically, we are wasting one real DIGITAL pin just for store logic and as a EN (enable) pin for the TIMER.
Starting from v5.0.0, instead DIGITAL we will use vDIGITAL component for the rule and EN (enable) pin for the TIMER.
This is a simple example, but in the system with more complex logic, there will be much more saved real pins by using Virtual Pins - elements (vDIGITAL, VTIMER, vCOUNTER), used only for store the logic states.