Does the Android app license key activation work offline without connecting to the Internet?

Hey Cryptomator Team.
I am setting aside a smartphone for cold storage to keep my Bitcoin wallets and other secure data. I am leaving this device completely detached from the Internet right from the installation of the stock ROM. Everything is done locally.

I want to install the Cryptomator app from your GitHub. Does the app connect to a Cryptomator server to authenticate the purchased license key or does it happen locally on the app?

The verification of the license key does happen locally without any server involved.