Target API level requirement from late 2018

You should first understand the difference between TARGET API and MINIMUM API Levels.

As a reminder, target API level is different from minimum API level. As the name implies, minimum API level is used to declare the lowest version of Android an app supports. The target API level is technically defined as the version of the operating system an app was tested to work with; but in more practical terms, it's used to define a set of behaviors an app expects from the operating system.

Please follow this link to view the complete source of this information: https://www.androidpolice.com/2017/12/19/play-store-require-new-updated-apps-target-recent-api-levels-distribute-native-apps-64-bit-support/

Just update your compileSdkVersion and targetSdkVersion to 26 (or better to 28). And read about minimum api version and target api version. It`s important to understand. https://developer.android.com/guide/topics/manifest/uses-sdk-element

What does this mean?

What it means is, you should ensure you have set targetSdkVersion to 26 in your build.gradle and your application is compatible with Android O behavior changes.

Does this mean that I will not be able to develop application compatible with versions smaller than 8.0?

You can set minSdkVersion lower than 8.0.

This would result in a "death" of all devices with version other than 8.0 ... Or is Google thinking about releasing android oreo for all devices on the market?

The distribution rate for Android O is still around 6%, which means older versions still constitute around 94%. They cannot implement drastic changes for this reason. Older OS version will be still supported until the adaptation for Android O changes drastically. It could be challenging because it involves adaptation from huge number of manufacturers.

If you are uploading your app as your first release, then you must ensure you are compatible with Android O.

For updates to existing app, the deadline is November.

onsole, Android Studio, and Firebase. Start survey Meet Google Play's target API level requirement

Bad interpretation of the message ?

Actual statement in English from site is:

Google Play will require that new apps target at least Android 8.0 (API level 26) from August 1, 2018, and that app updates target Android 8.0 from November 1, 2018.