Lint: "Newer Library Versions Available" when using variables
This is not an exact answer to the question. I had the same concerns some time ago (had declared global vars and referred to them from build.gradle files).
I've found gradle-versions-plugin library, which resolved my concerns.
It will prompt with detailed info after ./gradlew dependencyUpdates
In Android Studio, go to the Analyze menu and choose Run Inspection by Name -> Newer Library Versions Available. Choose Whole Project and wait for your results.
The easiest way I have found (AS 3.6.3) is to open the project structure with Ctrl+Alt+Shift+S where there is a Suggestions tab:
