I've tried to sign my apps the same way I did for Google Play Store, but App Lab won't accept them. There must be some new way to sign apps I'm not aware of. Can anyone who's successfully submitted to App Lab tell me how they signed their apps in the Unreal Engine?
I ended up needing to change minsdk (in project settings) from 25 to 23 in order for "v1 signing" to read 'true'
https://developer.android.com/studio/command-line/apksigner navigate your command directory to apksigner (C:\Users\myusername\AppData\Local\Android\Sdk\build-tools\30.0.2 for me) and use 'apksigner verify --verbose pathtoyourapk\app-name.apk' to check