Pythonista 1.6 is only supported on iOS 8 or later. Numpy was added with pythonista 1.5. Pythonista 1.5 is only available to devices running iOS 7 or later. If your device only supports iOS 6, you're out of luck. Check Settings>General>Software Update to see if your device can run iOS 7 or later.
Welcome!
This is the community forum for my apps Pythonista and Editorial.
For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.