Android & Docker on Ubuntu 20.04 update! 
This build fixes an expired GPG in the Yarn apt repository, as we as latest security patches from Ubuntu.
To select these Stacks you just have to open your app on bitrise.io,
go to the Workflow tab (Workflow Editor), and on the Stack tab select the Android & Docker on Ubuntu 20.04 or Android & Docker on Ubuntu 20.04 option and your next build will start on the corresponding stack.
*Note: you can now select separate stacks for separate workflows!
Read more at: Per-workflow stack selection is here! - Bitrise 1.*
You can find the system reports here: bitrise.io/linux-docker-android-20.04.log at master · bitrise-io/bitrise.io · GitHub
If you’d like to add additional tools to be pre-installed you can find the instructions on GitHub 1, for both the Linux and for the macOS stacks.
Information about Stack types & update schedules can be found here: How are the bitrise.io stacks updated and with what frequency? What's the stack deprecation / removal policy?.
Happy Building! 