Hello 
I’m glad that Unity is finally moving to a newer Version of the .NET runtime and the C# language.
What are the plans of keeping up to date once .NET 4.6 and C#6 have been rolled out?
C#7 Release is around the corner and features like ref returns and native tuples seem to be almost tailored towards gamedev.
Great if Unity will support C# 7.0. New language features is awesome!
I would love if Unity added C# 7.0! All those new features + the other features from previous C# versions would be so awesome! 
Please Unity!
As mentioned in various other posts we’re planning on staying closer to the latest compared to the past. But we have to get over the initial hurdle of updating to .net 4.6 but as you can see here we are on a good way with that
@Schubkraft was .Net 4.6 support C# 7 when ever it released?
Not yet. We released the updated compiler in 5.5. The next step is to the new Mono version but using the same older .net profile. After that we’ll be updating the profile.
We are doing it this way to keep the disruption as small as possible and do one step at time but do it right.
To clarify a bit, we’re now planning to release a new Mono runtime and the upgraded .NET 4.6 profile at the same time. Things are still up in the air, but this is the current state.
Not however that this release will not yet have C# 7 support. That is planned for a later release though.
Thanks for your clarification
I wish after C# 7 support. Unity next version would have new API to utilize return ref. Such as matrix and other struct manipulation
Don’t worry, we’re working on that as well. We are members of the .NET Foundation, and have been working with other members to the future of C# to allow for things like this.