Once logged in to the customer portion of the Keynote website you are able to set up notifications for when Keynote adds or updates software or documentation.
To do this first select the folder that you would like update notifications for. Then click on the bell icon in the upper right corner of the page:
A selection box will appear. Select Message and when you are logged into the Keynote website you will receive a notification if files have been added or updated. Select +Email and you will also receive an email notification.