Problems with Vikunja-Apps

I'm currently using Vikunja. It's self-hosted. It works very well in the browser. However, I'm having some problems with the two iOS apps from the App Store:

Firstly, I can't move tasks into projects – where is the "Move" button? Secondly, I can't upload files as attachments due to insufficient permissions.

With the "Kuna" app, I also have the problem that it keeps losing my login credentials. Are these known bugs?