Unity Cloud Build - target Android release

Looking in the Cloud Build FAQs, I see this:

Which Android SDKs does Unity Cloud Build support?
Unity Cloud Build supports most recent Android SDKs, including for Android 4.0 and up.

I used UCB to create an Android build of my prototype; this build installs fine on my phone on 7.1.1, but refuses to install on a tablet on 5.1. I presume this is because of the SDK version used to create the build, so I went looking for a way to tell UCB which Android version to target. I can see how to configure the version of Unity to use for building, but not the version of the Android SDK. Is there a way to set this, and if not, how can I change (indeed, how do I even know?) the minimal Android version required for my game?

Cheers,
Wayne

 

same
I cant find even in the ucb full log