This release reworks NeoPixel to use PixelBuf for the internal pixel buffer. On Blinka and CircuitPython < 5 it now requires the `pypixelbuf` (2.0.0+) library to run. It implements the same API as `_pixelbuf` in CircuitPython 5.x. NeoPixels manipulation should be faster when using the native implementation.
So, if you are still using CircuitPython < 5, then either 1) upgrade to CircuitPython 5.x, 2)use NeoPixel < 6, or 3) install pypixelbuf.
If you are Blinka, please make sure you have `adafruit-circuitpython-pypixelbuf` >= 2.0.0 installed as well.
To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-neopixel`.
Read the [docs](http://circuitpython.readthedocs.io/projects/neopixel/en/latest/) for info on how to use it.