FWIW, I’ve installed and configured version 1.2.0 on several multisite installs and the plugin seems to work without problems.
Network activation works, the only downside is that you have to adjust the plugin settings for each site separately.
On Site 1, all notifications are enabled right off the bat, while on all subsequent sites, they are disabled by default. If you have a lot of users, you’ll want to perform the plugin activation and configuration when there is little traffic, to minimize impact on users who want to reset their password during those minutes.
That being said, it would be very convenient if one could manage the settings for the entire network from the network admin.
Hope this helps!