Hey Unity Alpha users!
The 2022.1 release of Unity brings supports new .NET APIs via .NET Standard 2.1. It also includes full support for all C# 8 features. Please respond here with any questions or issue you find.
Note that these changes have also been back ported to 2021.2.
You can find a rich discussion thread about Unity’s .NET ecosystem plans here: Unity Future .NET Development Status
What about C# 9.0 and .NET 5/6 ?
What about reading the linked thread? The first two posts address your questions.
That was half year ago and for Unity 2021
there we talk about possibilities of Unity 2022 so repeat of these 2 posts there but for Unity 2022 will be very welkome
The thread has been receiving regular updates so it’s creation date is not a measure of it’s current information.
But it still about Unity 2021 to the last message and this one about Unity 2022
Many of the features that publicly landed in 2021.2 started out in the 2022.1 (non-public) alpha, as noted in that thread.
Also, just a month ago, [Josh replied]( https://discussions.unity.com/t/836646 page-6#post-7459993) regarding .Net 6:
Josh’s communication regarding the recent .Net updates has ben excellent, so I really don’t think it helps to ask him the same questions over and over again.
Since that thread is more general non-version-specific information about .NET ecosystem updates, I’ll continue to post on it when things change.
For this thread, we’re focused on 2022.1 alpha issues. From a feature set perspective, that will be C#8 support and .NET Standard 2.1 support. I don’t expect any additional .NET features to ship in 2022.1 alpha releases.
So right now .NET 6 support looks like 2022.2 or later - I don’t have enough information yet to be sure though.
did we have any hints when 2022.2 will ship
Most likely sometime during the last quarter of 2022. 
And LTS of it somewhere between March-May 2023 
But who cares the LTS version anyway, because we have already moved on to 2024.1 alpha
Haha, that’s true if you want to get your hands in the latest tech/features/and improvements, but you wanna stick with LTS for more usability/bug fixing/and long term development
It’s pretty funny that whenever you try to use nullables, e.g. myObject?.myValue, Unity says “nope don’t do that.”
Blog post 2014 
https://blog.unity.com/technology/custom-operator-should-we-keep-it
The answer should have been “No, don’t keep it”