PyPortal has been refactored and is now a package instead of a module, so replacing the file with a folder will be necessary. Also, you will need the PortalBase and FakeRequests libraries now. However, no code changes should be required.
To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).
Read the [docs](http://circuitpython.readthedocs.io/projects/pyportal/en/latest/) for info on how to use it.