Nova Launcher 5.1 is now out of beta
Nova Launcher 5.1 introduces Dynamic Badges - a new way to peek at notifications. The feature picks relevant images from notifications and shows them to you (next to an app's icon) instead of just showing numbers. So, for example, instead of seeing that you have 3 new messages, Dynamic Badges lets you see from whom these messages are, without opening the Messenger app - check out the image on the left.
As a side note, a beta build of Nova Launcher 5.1 has been available since March. However, being a beta version, this was unstable, and you had to join an opt-in beta testing program to download it.
The final, non-beta Nova Launcher 5.1 can be downloaded by everyone from Google Play via the source link below.
Things that are NOT allowed: