Site Change Notifications

Hey everyone, I'm looking for options to let users know when there's been a change to the website. Each of my clients has their own password-protected website. I use blog-pages and blank-pages on the website, and post content updates into each one.

Last year I used Zapier for text notifications whenever there was a change to their unlisted blog page. This year, since I've converted to full password-protected domains for each client, I've been unable to figure out notifications. Text notifications would be ideal, but email would work fine. Anyone have experience with this?

Thank you for reading.