My b2evolution Version: 1.10.x

I notice that users can choose whether or not to "subscribe" to your blogs after they register. But I can't see how, from the back office, to change the blogs to which each user is subscribed. So if I create a new blog, I would need to email all of the subscribers of my existing blogs and ask them to go into subscribe again and add the new blog. Is there another way?
Thanks.