They say the steam version has had a small patch. I was wondering if the GOG one also has also had this patch?

Aha, veeeeery interesting question ! I'm looking forward to see an answer to this.

While my post isn't useful in the sense it doesn't answer to the question, it will show you're not the only one interested in this subject...

I'm curious to see as well seeing that the steam version of this game has reviewing claiming everything from game breaking bugs to an incomplete tutorial.
Sorry that my post isn't really a response but I'm glad to see there are others that are concerned about lack of updates being provided to GoG users.

The update mechanisms of GOG and Steam are different. GOG is largely based on rolling out installation and patch files and let's users run those files themselves, while Steam has a tight control over what users have installed (GOG moves in a similar direction with Galaxy) and manage the installation of patches centrally (unless the user switches that function off).
Both approaches have their advantages and disadvantages, and different people feel differently about them - and I'm not going to discuss them here. But one consequence is that Steam tends to roll out patches quicker than GOG, as it's easier for Steam to fix issues with patches (which are not so rare ...).
Bottomline is that you may have to wait longer for a patch on GOG than on Steam (and it has happened that GOG has refused to roll out a patch completely because it was too buggy, and has waited for those bugs to be fixed), but you have a higher security that the patch doesn't screw up your game.

PS: I just had a quick look at the Steam forum, and it doesn't look like there is a patch available yet. Quote from Soaphog 1 hour ago: "We will provide more information about the fixes as and when I have an update."

I think it was a 'hotfix' which is not a full patch i guess. I used the term 'small patch' but 'hotfix' would have been more accurate. One of the users was complaining it brought new issues. So maybe GOG's approach is the better one. But sometimes hotfixes can be pretty effective.

"Hot fixes" or "small patches" - doesn't matter, but I agree that they can be very effective. Some people accept the risk that patches or fixes introduce new problems, others want to avoid or at least minimize that risk.
From GOG's perspective, to offer a patch which makes a game unplayable for its players might be a high business risk due to their "asynchronous" rollout method, as they don't have direct access to their users' PC's. As far as I'm concerned, Steam's direct access to MY PC makes me nervous, to say the least (yes, I could uninstall Steam, I know ...).

Well, i've gone for the GOG version as I do generally like their business model and it's good to support alternatives. I still favour steam for multiplayer games. So Rezrog is on version 1.0 but i havent had any issues with the game so far. It's a nice game and I hope it can grow to be popular and well supported. Maybe even expanded on.

Steam does have a 1.01 patch, which fixes lots of small issues, espeically with saves:

"Save system updated. We have rewritten part of our save system to reduce the amount of issues with the progress loss. The problem is still there but it should happen less often now
Shared stash will properly save the items now after the save system update
Tutorial system received some fixes, people will no longer get stuck if they skipped the return to tavern part
Summoned minion mana return will no longer cause any issues with other actions requiring mana to use
Crystal objective prop interactions with multiple skills is fixed, some of them were stealthy and while they were not seen as soon as the problem occured, were messing with the future interactions along the line
Preliminary fixes on skill exp book issues
Level reward boxes now properly scale with the dungeon level
Spike trap/Drain floor will no longer damage person who is attacking an enemy standing on those
Collision issues fixed with big 2x2 monsters"

So get with the game, GOG, and make the patch/hotfix available here, because I'm tired of the stuff disappearing in my shared stash every time i want to play again.

I just bought this yesterday, and it's been fun, but if GOG doesn't get the patch soon, I'll refund it and go buy it on Steam.

I am also waiting on the patch ! Tbh though I think we might need to wait for a bit more than just 1.01 or 1.02 as the game does have a few problems. Seems like a fun game but I am feeling impatient to play it !

Installing the patch appears to have wiped my progress and made it impossible to click on any characters. Will try to re-install.

UPDATE:

Apparently this is an issue on Steam as well, and you have to delete your progress.json file (Appdata/locallow/soaphog/rezrog/save) in order to be able to play again. Of course, the progress is still all lost.

If every patch is going to wipe your saved games (including legacy crystals), there doesn't seem to be any point to playing right now.

Glad they added it though, not long after the steam one. So nice one devs.