title: The Oreo version of my app can't comprise Nougat version?
body: <p>I have some questions about my application.</p>
  
  <p>1) 1 year ago I released the application in Google.<br>
  2) I had many tests with my phone (the version is 'Nougat')<br>
  3) the application is working well on my phone still, but another phone which is android version 'oreo' is not working well.</p>
  
  <p>So I guess 7.x and 8.x have some differences?</p>
  
  <p>I don't understand why the 'oreo' can't comprise 'nougat' application.</p>