There is not much specific information about Exocet RS5 2018 available, so posting a few pictures and observations. Also I owned a 2013 model, will talk about the differences.
Comparison of the 2 models: while the outline is similar, the main differences are in the tail shape and cut-outs, which are much more modern, as well as the fact that most of the volume now is at the back with very little left in the front.

The new board is 1 cm wider and 128 liters, 6 more than the older one

The tail showing the wings and larger cut outs

Here you can see the volume distribution, more than before in the rear and less than before in the front
On the water:only 1 outing so far, in medium wind 16-20 knts with 8.7 and 7.9 slalom sails, and 44 sonntag fin.
The main difference is how much higher the board floats on the water now, still maintaining that stability that the previous model had, but feeling more lose in the acceleration.
Secondly it is easier to carry the 8.7, feels a lot more natural and comfortable; I was using the older board with 7 and 7.9, this one has more range 7 to 8.7.
For jibing I need to get used to the different volume balance, I dug the front rail a couple of times.

I will keep adding all my sessions here in the future, if anyone interested keep visiting the link:
martignoni.id.au/summary.php?board=Exocet_RS5_2018&sort=date And if anyone has the same board please post your observations.