For those working with and/or supporting multiple WordPress sites, I have found ManageWP to be a helpful service.

From their site:

All your sites under one dashboard! ManageWP helps you manage all your WordPress sites from one dashboard, keeping them updated and secure.

I don’t get anything for telling you about them, I just like them and appreciate what they’ve permitted me to do and accomplish a little more easily as I support and manage multiple WordPress websites.