To know the Spine version, click on the Spine logo in the upper corner, you should see something like this:
If you're learning how to use Spine, I definitely recommend fiddling on the latest version, that has more features and will give you the best experience. Spine should keep itself up to date, so if you're just fiddling with it, the latest version will give you the best experience. to do so click on the spine logo, go to settings:
Then choose latest:
Then save, restart Spine, and you should be good to go! you may need to re-download the Spine installer if you haven't updated in ages, to do so, tell your friend to follow the link he received when he bought Spine and get the new installer from there.
Regarding the script, I just tried to import a bunch of jsons made with the new script into Spine 2.1.27 and they all worked.
Make sure to get the script from this link: spine-scripts/photoshop at master · EsotericSoftware/spine-scripts
This video also shows the process from installing the script to importing to Spine:
VIDEO