From the email:
As of Feb 26, 2021 after market hours, you will no longer be able to use your current Polygon.io data feed via your Alpaca API key. However, Polygon.io will provide a 100% discount coupon for March to our users who are using Polygon.io data. You need to take action immediately to ensure you retain your access and will need to create an account on Polygon.io’ website.
Please use coupon code ALPACA during checkout on Polygon.io to claim your free month.
After your free month, you will be charged the regular price for Polygon.io. For the pricing details, please visit https://polygon.io/pricing.
We aim to make the transition as smooth as possible, therefore we will be sharing more information with you about the new features in the upcoming week along with tutorials and documentation.
They’re giving us a month of free Polygon usage, so there’s no reason you can’t continue trading. In the coming week they will give us more info about the new features.