I recently bought a brand new 7'6 surf pro (92 litres) to replace my 2019 8'1 surf pro (103 litres).

It's noticeably lighter due to the drop in volume, but I don't see much difference in the actual construction.

I've only surfed these two JPs, but compared to other SUPs I've ridden the JPs are a very light & tough construction by comparison.

Hopefully someone else can comment on new JPs cf 2016/17 versions

martyman said..
can't see why they would go backwards.

Why? Everything is a compromise, notably between the "big three": price / durability / weight.
Brands can change their compromise with time, according to what they perceive of the demands of their market.
Going "backwards" on one of the 3 may mean going forward on the two others...

And if inflation strikes, they may want to adjust the compromise to keep their retail price from skyrocketing.
Some brands reduced the amount of carbon in their carbon models, for instance.

Disclaimer: these are general remarks, I have no idea of what JP is doing.