The Spine installation is the "Spine launcher". It can run any version of Spine we've ever released, except for some beta versions. The full list of versions is here:
Spine: Changelog
Unfortunately we had to make a change to how the editor files work during the 4.0-beta. I'm afraid versions >= 4.0.00-beta and <= 4.0.54-beta are no longer available.
I think your best course of action is to update the spine-cpp runtimes to the latest 4.0-beta version. You can export your Spine projects using the CLI. It's almost always worth setting up scripts to export all your projects as part of a build process. That ensures all your exported data is up to date and exporting your projects is necessary to move to newer Spine Runtimes versions. For example, here is the script we use to export all the Spine examples in one go:
https://github.com/EsotericSoftware/spine-runtimes/blob/4.0-beta/examples/export/export.sh
Lastly, I would suggest not to use JSON in your final app. Binary is smaller and loads more quickly. That alone could make it worthwhile to setup an export script.
