@Sato Hi!
I misinterpreted your question, sorry!
Your concerns are totally valid and understandable.
It should be a possibility to create a custom GUI-O application instance tailored to your needs. This means you get an apk that you can distribute to your users on your own terms. If you develop a product with this application instance, you are not affected by the main GUI-O application branch. Even if GUI-O loses support, your product is safe(er). You don't get any new features, but your product lives on.
But in order to get a custom application and some support for future updates, fixes, etc., this would be more expensive for you. Why - because I need to maintain your custom application version.
I currently don't have a business model in mind (working on it...), so I cannot give you any more details. But I am glad that you've put this questions forward for debate.
What do you think about this?
P. S. Your custom app could probably also be distributed via Google Play.
I will probably create a new post on options to distribute GUI-O (or GUI-O variant) to end users. I hope I get a lot of feedback from you and other people in similar situation. This way, we will be able to shape together how to make GUI-O more distribution friendly.
Regards,
Klemen