It doesn't really matter. Your app obviously doesn't use anything that actually requires SDK 31 as it compiled under SDK 30 and as Android is generally backward compatible it will run on an SDK 31 device and many earlier ones assuming you set your minSDK correctly. The only thing that I can think might trip you up is if there is something, like a permission, that got tightened up under SDK 31 compared to SDK30. For example if you target SDK 28 your app can access the entire filestore with PERMISSION_WRITE_EXTERNAL_STORAGE but if you change the target SDK for that same app to SDK 30 it will be subject to SDK 30 restrictions and will not be able to directly access any other than a few select folders and types of files.