@momijigari With the JsonRollback tool you can specify either 2.1 or 3.7 to perform the following conversions:

2.1: supports going from version 3.3.xx to 2.1.27.
3.7: supports going from version 3.8.xx to 3.7.94.

It's been a long time, but if I remember correctly, there's not much (or any) difference between 3.7 and 3.6 JSON. Are you sure you need to do a conversion?

Thank you, Nate.

So I can convert to just 2 versions of Spine?

My problem is that we have been doing all animations in Spine 3.7.94
But my customer's game engine supports 3.6.53, and they require exports for 3.6.53
And not all animations can be manually converted to 3.6 (by exporting JSON from 3.7 and then importing those into 3.6 Spine), some just don't import.
So I'm tryin to find a solution here.

We would have to first determine why your 3.7 JSON doesn't import into 3.6. Can you post or email one of the problematic JSON files? contact@esotericsoftware.com

Hi, I'm trying to export json file from the spine 4.0.51 to 3.8, but I am getting this result on terminal here on my mac:

Error: Could not find or load main class com.esotericsoftware.spine.JsonRollback
Caused by: java.lang.ClassNotFoundException: com.esotericsoftware.spine.JsonRollback

Sorry, you cannot go from 4.0 to an earlier version. 4.0 stores the curve information in ways that cannot be represented in older versions.

Hi, I'm trying to convert a file from version 3.8.99 to 3.7, but it gives me the following error:
Error: Could not find or load main class com.esotericsoftware.spine.JsonRollback

I have the skeletonViewer-beta.jar file in the same folder as the file I want to convert and I just installed Java

@javier_mh94 Sorry about that, we've uploaded Skeleton Viewer 4.0.53-beta which fixes that problem.

Thanks Nate! Now it works perfectly

@jhonatanssilva We have updated JsonRollback in Skeleton Viewer 4.0.54-beta to support specifying a version of 3.8 to go from 4.0.xx to 3.8.99. However, there are some drawbacks: all curves will become linear, separate translate, scale, shear, and color timelines are lost, and constraint translate Y and shear Y are lost.

We have updated JsonRollback in Skeleton Viewer 4.0.54-beta to support specifying a version of 3.8 to go from 4.0.xx to 3.8.99.

So that means we can go back from 4.x to any 3.8.x maybe even 3.7.x?

p.s. Cant open beta jar, Java updated

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/badlogic/gdx/ApplicationAdapter has been compiled by a more recent version of the Java Runtime (class file version 57.0), this version of the Java Runtime only recognizes class file versions up to 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

Hello everyone! We are trying to downgrade from version 3.8 to an older one. Prints a lot of errors. Then we tried to view the animations separately using skeletonViewer 3.8.99 - the black screen blinked and nothing happened. Java is updated.
As a test, the old 3.6 file with skeletonViewer-3.6.53 works perfectly

Hello, what errors are you getting precisely? did you already try to downgrade the project following these instructions?
Open project in an older version

Resolved

Hi! I'm trying to downgrade a json from 3.8.99 to 3.7 and having issues. I'm an animator, so I'm struggling with these kind of things.

I exported the .json with Nonessential data checked (and everything else unchecked).

I downloaded the Skeleton Viewer 4.0.54-beta from this site: http://de.esotericsoftware.com/spine-skeleton-viewer and put it into a folder on my desktop named "json" together with the .json I need downgraded.

I downloaded and installed the most recent Java version (Version 8 Update 281 Build 1.8.0_281-b09). I also checked, there is only one installed and it's version 8.

Then I ran this command:

java -cp "C:\Users\kerst\Desktop\json\skeletonViewer-beta.jar" com.esotericsoftware.spine.JsonRollback "C:\Users\kerst\Desktop\json\MainChara.json" "3.7" "C:\Users\kerst\Desktop\json\MainChara-2.json"

But I'm getting the attached error. What does it mean?

EDIT: I found the issue! I had the wrong Java version. I downloaded regular old java from java.com, but the correct one is the Java Development Kit you can find here: https://www.oracle.com/de/java/technologies/javase-downloads.html . You need to install it, reboot and then it should work.

Noody! THANK YOU!!!! With the Java SE Development Kit 15.0.2 it works!

warmanw ha scritto

We have updated JsonRollback in Skeleton Viewer 4.0.54-beta to support specifying a version of 3.8 to go from 4.0.xx to 3.8.99.

So that means we can go back from 4.x to any 3.8.x maybe even 3.7.x?

Sorry I missed this. Yes, you can. However, as of 4.0.68-beta we've made it easier: you can choose an older version when exporting JSON.

Immagine rimossa a causa della mancanza di supporto per HTTPS. | Mostra Comunque

This is equivalent to using the JsonRollback tool, but is easier. Going back to an older version may still lose data and may still require manual fix up, such as deleting attachments or constraints that do not exist in the older version. Exporting to an older version is still not a recommended workflow, it is provided only to help recover work after from the catastrophic situation where a newer Spine version was used unintentionally.

Thank you, Happy tears.

Hello, I have around 300+ spine exports, And the project i need to update is very old, spine 3.x. I Don't think i'll be able to find all the spine projects.
I need to update it to 3.8.
Is there a way to change all the json files (assuming only changing the json will make it work).

@bilalmirza The process is: run 3.8, convert JSON to a project (.spine), run 4.0, export JSON from the project.

You can write a script to do it. I recently posted more information and the commands here:
Spine-Unity 3.8 to 4.0 Upgrade Guide

Thanks! just what i needed.
Sorry I missed that post, my bad.

All files were converted via tool you mentioned. Everything works perfect except for 1 file. Any idea why it could be?