We have just been notified by Quandl that their YAHOO and GOOG databases will be removed on June 30, 2017. As a result, the Yahoo VIX dataset will stop updating on Quantopian.
Fortunately, Quandl has another VIX dataset, sourced from the CBOE, already integrated on Quantopian. The API of the CBOE version is very similar to the Yahoo version. The main difference is that the columns in the CBOE version are called vix_close, vix_open, vix_high, and vix_low instead of close, open, high, and low. Other than that, you should be able to load the data in the same way in your pipeline.
The dataset may vary a little from the Yahoo version, so you should consider inspecting the new dataset before using it. A good way to inspect the data is to use the interactive version in data which can be obtained by using the following import statement:
from quantopian.interactive.data.quandl import yahoo_index_vix, cboe_vix
We apologize for the inconvenience. Please let me know if you have any questions.