Is GOG getting the updated demo that was released today, or is it Steam only?

The latest Kickstarter update has instructions for getting the "Steam Next Fest Demo". There is no mention of GOG.

(I believe they had a prior beta release that was also Steam-only.)

It's already available on GOG and you should try it now.
Only a beta but it really takes me back, in a good way.

Where?

The demo currently on the GOG store is the medical demo not the new one showcased at next fest.

edit

played the steam demo. Its not bad. I never played the original so how faithful it is i dno. Not sure its worth £34.99 though.

I ended up playing on steam. Aside from the melee and a few technical quirks, it's fantastic.

Really looking forward to it.

The melee feels like a bit of an afterthought since there are three ammunition weapons to use and I had little trouble finding ammo for each of them. I will say that I liked the introduction of the SS2 wrench as a melee weapon!

It certainly feels like an afterthought, which is unacceptable since it's your introduction to combat. Especially odd since, like you said, they've added a brand new melee weapon.

You'd think they would try to make it fun...

I'm hoping that since the demos are either Alpha or Beta builds we will get a release version that features fun, impactful melee combat.

Of course, that depends on the game coming out..and Nightdive not relying on massive patches to fix minor problems...and Nightdive knowing how to balance the melee combat with the ranged combat...

Now I'm getting worried.

Played the Demo this Week, Meele seems to be a Fallback Option if you go out of Ammo.
I never played the Original, so is it so important that People are focusing so much on it?
I personally wouldn't know what to improve without to put too much Focus on it, a Block Feature?

I hope it will be possible, to play through the game with sneak/hack...don't like melee/shooting anymore. Take advantage of the environment, build traps etc.
Just like the first Deus Ex, where you don't have to kill !