Android compile sdk effect on final binary

Question

Given an android project developed in android studio. What effect does the compile sdk version has on the final apk.

So let's say I compile the same project with sdk level 15 and then do it with sdk level 23. Let's ignore the compile time warnings or error etc and assuming both compile fine

what difference does the end result apk file have ?

Thank you

Answer 1

From the docs. From what I read you can trigger optimisations and features with this setting, but it greatly depends on minSdkVersion and maxSdkVersion

targetSdkVersion

An integer designating the API Level that the application targets. If not set, the default value equals that given to minSdkVersion.

This attribute informs the system that you have tested against the target version and the system should not enable any compatibility behaviors to maintain your app's forward-compatibility with the target version. The application is still able to run on older versions (down to minSdkVersion).

As Android evolves with each new version, some behaviors and even appearances might change. However, if the API level of the platform is higher than the version declared by your app's targetSdkVersion, the system may enable compatibility behaviors to ensure that your app continues to work the way you expect. You can disable such compatibility behaviors by specifying targetSdkVersion to match the API level of the platform on which it's running. For example, setting this value to "11" or higher allows the system to apply a new default theme (Holo) to your app when running on Android 3.0 or higher and also disables screen compatibility mode when running on larger screens (because support for API level 11 implicitly supports larger screens).

There are many compatibility behaviors that the system may enable based on the value you set for this attribute. Several of these behaviors are described by the corresponding platform versions in the Build.VERSION_CODES reference.

To maintain your application along with each Android release, you should increase the value of this attribute to match the latest API level, then thoroughly test your application on the corresponding platform version.

reference

Edit: (now that I got your question correctly I guess)

compileSdkVersion

The compileSdkVersion is the version of the API the app is compiled against. This means you can use Android API features included in that version of the API (as well as all previous versions, obviously). If you try and use API 16 features but set compileSdkVersion to 15, you will get a compilation error. If you set compileSdkVersion to 16 you can still run the app on a API 15 device as long as your app's execution paths do not attempt to invoke any APIs specific to API 16.

reference

So I would assume the resulting binary has some different pointers here and there.