As someone who has used this app for at least 6 years, I am very sad to see this happen.

I'm surprised they weren't able to get away with it after the change in extensions a couple versions ago. By not shipping extensions that have copyrighted content that should have been enough, similar to how emulators, services like Plex and torrenting applications survive.

It's effectively just a comic / manga reader that can be used for piracy when the right extensions are added.

Apparently that wasn't enough, and I can't blame open source devs for not wanting to start a legal battle with a profit-earning company.

For now, the app does allow you to add external repository's (list of extensions for various sources) that are still being updated, and I believe there are at least a few forks of the project that will survive for now.

All I can say is great work to the dev team for sticking with us until now and I wish you luck in your future ventures.