DanielWolf schriebRhubarb supports both Spine 3.7 and 3.8. I have no plans to change that. But it's good to know that there are people reliant upon version 3.7.
Regarding the tutorial: I've started working on it. But beside my job and my family, I'm afraid my time is rather limited, so it'll still be some days.
I'm happy to know that Spine 3.7 will stay supported. As for the tutorial, thank you for starting it, as for finishing it, Your main job and family should always come first.. I've subscribed with notifications for when you upload it and it's available.
I appreciate everything you do, Thanks again for Rhubarb!