Add EOL date for .NET 9

[richlander]

No description provided.

[mairaw]

Should we add end of support when the release is not supported yet?

[richlander]

We can bias towards transparency or a strict interpretation for preview support.

I suspect that 100% of users will appreciate this and 0% of users will be confused.

Somewhat related, I found this set of recommendations to be a good read: https://endoflife.date/recommendations

[Varorbc]

Why is it 36 months instead of 18 months?

[richlander]

Oops! My mistake.

[richlander]

Slightly more useful reply @mairaw ...

I think of the EOL date as being for the major version while our support policies cover what the support is for preview releases.

https://github.com/dotnet/core/blob/main/release-policies.md#support-phases

So, if a user concluded that Preview 5 was supported until the given date, then they would come to the wrong conclusion per our published policies. I suspect few users would have that challenge.

[mairaw]

I still find a bit misleading that .NET 9 shows up on this page under supported versions.

[richlander]

Ah. That part is a mistake. It should be under "Preview" versions. That sections keeps on coming (at P1) and going (at RC1). I can fix that.

[richlander]

#9363