Hello, The UNET multiplayer system is completely different to the system covered in the S1 and S2 tutorials, so basically those tutorials are no good for Unity 5.1 onwards.

I'm still using RAKNET from GTGDs Season 2 and running it in Unity 5.1 but am hopeful to see the transition occur from RAKNET into Unitys UNET since RAKNET will no longer be the supported framework. I do feel the tutorials still teach you a lot and they should still help others understand the basics of networking. Especially since UNET isn't quite stable yet as we have seen through GTGD's pain staking process of testing & evaluating in the UNET tut series. More interesting though is going to be the price point comparison between UNET and Photon Networking as this will ultimately affect who will follow the tutorials GTGD and others release.

So following the S3 I will need to upgrade to Unity 5? I am a Pro user for Unity 3 and 4, but have been hesitant in upgrading to Unity 5, but gladly will to follow these tutorials.

Made the upgrade to Unity 5 personal edition. So far following the S3 tutorial, everything is simpler than S1 and really surprising me in a good way.