There's a new version of Netflix in the Play Store, but it's not rolling out to everyone. You'll only get the latest v5.1 build if you join the new Netflix Play Store beta. Netflix is kicking off its beta with some cool features including a mobile data saver.
A single TV episode can eat up a few hundred megabytes of mobile data, which is one of the reasons T-Mobile is pushing its Binge On service. In the new version of Netflix, you can lower your data usage by turning on the mobile data saver. We've looked at the code in the app, and this feature lowers the bandwidth available to the app when it detects you are not on WiFi.
The new Netflix client also adds support for Google Play billing, indicating that subscriptions in the app are on the way. We've confirmed from the code this is happening, but pricing is delivered by the Play Store itself, so we can't say how expensive it will be. Google takes a 30% cut of transactions, so some apps use higher prices than what you'd find on the web to compensate. If you don't want to join the beta, we've got the new version on APK Mirror.
As some have pointed out, the data saver option isn't new. However, it seems to be showing up intermittently. We didn't see it on a test device until updating to the beta. I have also been unable to get the option on my phone even with the beta. This might be a server-side switch of some sort.
Apparently Netflix wasn't ready to throw the switch on the beta, and has closed down new signups. The data saver option is also part of a wider test unconnected to the beta that will come to the app later.