Here's a continued version with couple fixes and maintenance:

https://mods.vintagestory.at/ropebridges

If you're the original author, just let me know if you want this removed in comment under my mod

i have over 30 mods in 1.21.6 and it works fine for me

This mod work correctly for me 

It's a pity that the mod is abandoned. It's a fantastic idea to use suspension bridges for building. I hope someone will continue this concept in their own mods. Version 1.22 is coming soon, and maybe there will be rivers

Works in 1.21.1 too!

works in 1.20.4, placement kinda sucks. wish it was like monkey bridges or rope ladders where you have 2 points, line them up and drop the bridge. as is, you can't place them where you're standing, so you can't sneak to a block's ledge to place them along your desired path. you need to place scaffolding to cross distances with these bridges. i'd prefer the rope ladder method, but an alternative of some kind is really needed for this mod. otherwise, it's great!

Update please!

This works in 1.20 for me. (though I do not use Wildcraft Trees)

primitive survival got (monkey bridges) too i think so you can get so there too.

I used to have some Wildcrafft Trees versions of these bridges in my base... but then all the Wildcraft Tree stuff was moved out of the game domain and all my bridges vanished. 😀

I can whip up a little content mod to fix that. I'm happy to share that code with you if you have any interest in updating this mod. Otherwise I can just upload my own stuff. Let me know if you're interested!

Posted it here: https://mods.vintagestory.at/ropebridgescompatibility

Versora
Thanks for letting me know 😊

I have not built anything from this mod, but my game doesn't throw a fit with it active, so yeah. I have the perfect world to test this on since at spawn  many deep chasms and ravines almost killed me because tall grass is a pain the ass, lol. also on 1.19.1 btw.

Edit:

Update:

It works on 1.19.1. No problems from my end.

Pervy_Sage
I haven't had a chance to try 1.19 yet.
It should be okay as this mod is simple json-only.

ozBillo Does this work with 1.19?

Sp0wN
OK. No Problem.

ozBillo
Add you mod for the server in our mod pack

Sp0wN
What did you want to use it for?

ozBillo
How can I contact you? Can I use your mod code with credit?

Working on 1.19-pre builds?

Still working on 1.18.5

Still working on 1.17?

Still working on 1.16.4

Apply these patches directly to these item files.

It's a json only mod at the moment which has it's limitations.
At some point I will convert it to C# which will make it possible to address some of the concerns you have.
I'm not sure how soon I will be able to do that.

Having different kinds of bridge form from a singular kind of block, or having just a bridge end and bridge part block would be good. its not very convienent to need to have 4 filled up slots in order to build a bridge. besides that this is a solid mod

According to VS discord wisdom, enemies can spawn in blocks, air and grass, with solid surfaces beneath, and because slabs (and, therefore Rope Bridges) aren't solid they can't spawn there.

That's a very good question. 
I'm not sure what prevents drifters from spawning on some blocks. Slabs, for example.
I'll ask over in discord.

Just wanting to confirm - these blocks can't have enemies spawn on them, right? Since they'll be a pain to light up if they do.

You can now download Rope Bridges for VS 1.15 here on ModDB 😀

Added a new version 1.1.0 for VS 1.15 pre versions.

You can download it from the Rope Bridges thread on the Vintage Story forum.