Hello!
Export a Json with nonessential data checked, then downgrade Spine and reimport it.
Make sure that in the project you are exporting there aren't any features that the older Spine didn't have, such as audio, because it will fail to import in this case.
Export - Spine User Guide
Import - Spine User Guide

Hi I am having same issue but 3.8 -> 3.7

with nonessential data checked on still old spine cant import/open json/binary files.

is there anyway to downgrade JSONs or maybe I can do it manually if you can tell me what major has changed ?

I found this post
Spine editor and runtime version management

downloaded corresponding skeletonviewer and rolled out the json
but same

to make sure I need to run the command on the same version of skeletonviewer to which I want to downgrade.
so if I want working json for 3.7 I run it on 3.7 version skeletonviewer

You would use the 3.8-beta Skeleton Viewer JAR to run the JsonRollback tool to go from 3.8 to 3.7. If you can't import the data after running the tool, please post or email the original JSON. contact@esotericsoftware.com

I tried first but it says

ERROR: Target version must be: 2.1 or 3.7
Usage: <inputFile> <toVersion> [outputFile]

:happy: It works :

just command is a little different

Hi

Can you kindly explain how to run the JSON Rollback Tool for someone who isn't used to working with command lines in the Terminal?
I am on a Mac and so far have the skeleton viewer running by just double clicking the JAR file. I was wishing to find a JSON Rollback button in the UI but that's not how it works is it?

Thank-you!

I was wishing to find a JSON Rollback button in the UI

I wish it was that way

but dont worry using command line is not that hard.

first you need to have Java installed.
https://www.java.com/en/

then just open terminal and write this command
java -cp skeletonViewer.jar com.esotericsoftware.spine.JsonRollback input.json toVersion output.json

example

java -cp "C:\Users\Arman.Arman\Desktop\skeletonViewer-beta.jar" com.esotericsoftware.spine.JsonRollback "D:\Spine Animations\skeleton.json" "3.7" "D:\Spine Animations\skeleton1.json"

here how to do
it is not very well visible in gif but I drag and drop files into terminal

Wow, how very nice of you... thank-you so much!

Thanks warmanw!

you saved my butt @warmanw!

Tried to use the command method to rollback a 3.8 file to 3.7, but I kept getting this error and not seeing my new .json.

Any help on this? Also, it seems like the Skeleton Viewer just refuses to open a .json I have and even Spine examples, even if exported from the matching version (3.8.76).

*Edit: Okay, I tried with another 3.8 animation, and it rolled back to 3.7 perfectly. So, I am assuming there's an issue with the first .json's setup within the Editor that's preventing rollback.

*Edit 2: Aaaaaand, I isolated the problem with one of my skins simply having no attachment... So it seems like I have to make sure no error reports appear during Export (except Slot visibility, cuz that seems to cause no problem).

Good find, we'll fix the crash when a skin has no attachments, thanks!

Hi,

Is it possible to downgrade versions from 4.0.75-beta to lower 3.8.99

thanks guys

There is a way to do it, but with losing some data regarding to curves.

Thanks a lot man

Hi,
This has just happened to me, but with versions 4.1.10 and 3.7.83, but alas did not work, would not import, there is no animation but the project is boned/skinned etc, I have in cluded some images of my export options.
Thanks

This thread from 2 years ago is pretty long. Probably better to start a new thread, but we're here now.

alas did not work, would not import, there is no animation but the project is boned/skinned etc

What didn't work? You don't import an atlas, you can unpack an atlas or export one. It sounds like import did work, if you see bones and attachments. Check your spine.log.

I have in cluded some images of my export options.

If you are trying to get a 4.1 project into 3.7, open in 4.1, change the JSON version to 3.7, export, import into 3.7. See here for the importing part:
http://esotericsoftware.com/blog/Importing-skeleton-data

Sorry about that, and thanks to your reply.

I was following Erika`s response and followting that, it seemed to work for e.m.
"Export a Json with nonessential data checked, then downgrade Spine and reimport it.
Make sure that in the project you are exporting there aren't any features that the older Spine didn't have, such as audio, because it will fail to import in this case."
Hence the images of my export setup.
P

When you export JSON, uncheck Pack since you don't need an atlas.