You can use the CLI to import JSON into a .spine file, though very old versions of Spine may not support this. In that case you'd need to use the UI. You should always keep your .spine file so you don't need to import JSON/binary.
As the error says, you specified -i and -o without specifying an action. What action are you trying to take? See:
http://esotericsoftware.com/spine-command-line-interface
To use 3.6 to import JSON to a project file:
spine --update 3.6.53 --input data.json --output project.spine --import
If this gives an error, you'll need to use the 3.6 UI.
Once you have a project file you can load it with any newer version, eg:
spine --update 4.2 --input project.spine --output path/to/folder --export json
