Even if you manage to install an app, the server side must still support the older API calls sent by that specific app version.
Below is a detailed breakdown of the most reliable methods currently available as of this writing. netflix ipa ios 511 best
If you prefer to keep your device in its original state but still have the IPA file: Even if you manage to install an app,
If getting the app installed proves impossible, you can try the web browser fallback. Open Safari, navigate to Netflix.com, and sign in. iOS 5.1.1's Safari is quite old, but Netflix is technically designed to run in major browsers. navigate to Netflix.com
[Desktop PC/Mac] ---> (Sideloadly / USB Cable) ---> [iPad/iPhone iOS 5.1.1] Launch on your computer.