According to Netflix, the default control setting will let users stream approximately 3 hours of TV and movies per gigabyte of data, which it determined as the sweet spot setting that "balances good video quality with lower data usage to help avoid exceeding data caps and incurring overage fees." Of course, since the whole point is personal customization, the controls let users on higher data plans up the streaming quality at their will, and vice versa.
The cellular data controls can be found in App Settings, with the various customizable controls available once you toggle off "Set Automatically." From there users can choose Low (4 hours per GB), Medium (2 hours per GB), High (1 hour per GB), or Unlimited options for streaming video in the app. An alternative also exists to shut off cellular data playback completely -- and only use Wi-Fi -- within the menu.
In addition to the cellular controls, the 8.4.0 update to Netflix on the App Store also brings 3D Touch support for Quick Actions right from the Home screen, VoiceOver improvements to navigation, and various bug fixes. Those who have yet to do so can download Netflix from the App Store for free. [Direct Link]