Nova Launcher's "L" update is out of beta, you can get the final version now via Play Store
Nova Launcher “L” update was in beta for some time now. You had to do a few steps in order to get that version of the app to your device. Well, this update is now available in its final release and you can download it via Google Play Store (link below).
We’re calling it the “L” update because the developer added animations, icons and so much more in order to make it look like Android “L”. Other than these additions to the application we also get some tweaks and improvements to its functionality (squished bugs and such). You can find more information in the Google Play Store or if you follow the link above.
Source: Google Play Store