As it has been already told the relative velocity of bodies has a limit equal to 1 and this limit is a result of definiton of the velocity see chapter: VELOCITY
Since in the FER (Four-dimensional Euclidean Reality - the name of the new Euclidean reality) all four dimension are in the same scale then the speed of light will be equal to 1
Considering propagation of quantum, we have to acccept assumptions according to which the observed speed of quantum will  be  equal  to  1.
On the left:
A body moving along trajectory t' is emitting two quantum: one is received by observer moving along trajectory t1, the second one - along trajectory t2
Assumption 1: The quantum is emitted along trajectory perpendicular to the trajectory of the body: t' being at the same time the space axes of both observers' frames
Assumption 2: The trajectory of the quantum is carried along a trajectory od an observer. If the quantum passes the distance Δx1 or Δx2 along its trajectory, the trajectory of quantum will be carried for distance respectively Δt1 or Δt2 along the trajectory of the observer
Assumption 3: in the vacuum Δxi = Δti
The speed of quantum is observed by each observer as euqal to V=Δxi/Δti =1 independently od the relative speed of observers (which is equal to the sinus of angle between the observers' trajectories, in the figure above: t1 and t2)
The resultant trajectory of quantum depends on the trajectory of observer receiving the quantum. It menas that each quantum just in moment of emmission knows where and when it will be received. There is no emmission of quantum anywhere into space. Therefore the emmission of quantum seems to be a result of some kind of instatnt interaction between two distant bodies.