I tried to do the Google workaround....new subscriber details are getting replicated in my Google sheets, and although I have set up notifications in the sheets so that I'm emailed about any changes (presumably the appearance of new subscriber details qualifies), I'm still not getting emailed about it. So frustrating. Have asked the Squarespace customer service person to request the subscription notification feature - I'm astonished subscriber notification from within Squarespace does not exist.