title: Firebase Analytics - audience by OS major version
body: <p>I was trying to create an audience in my Firebase Analytics to group users by major iOS version.</p>
  
  <p>So I created a new audience filtered by stream as to project contains more than just production iOS app and then I've set another condition to filter by <em>User Property -> OS version</em>. For iOS 11.x I've set it to <em>contain ios 11.</em> or I've tried regular expression <em>ios 11.*</em>. None of which worked, I always get 0 users, even though that on unfiltered dashboard such users exists.</p>
  
  <p>Does anynone know what will be the correct condition? Thanks</p>