Use APKPure App
Get 「グラブルアニメ」Viewcastアプリ old version APK for Android
It is an application that you can browse the official website and use the Viewcast function.
It is an application that you can use the Viewcast function (*) of "GRANBLUE FANTASY The Animation".
You can also browse the official website.
* User registration is required to use Viewcast.