.NET version 3 and earlier have reached end of support. You cannot re-deploy versions that use runtimes after their end of support date

## Announcement .NET version 3 and earlier have reached [end of support](https://cloud.google.com/appengine/docs/flexible/lifecycle/runtime-lifecycle#end%5Fof%5Fsupport). You cannot re-deploy versions that use runtimes [after their end of support date](https://cloud.google.com/appengine/docs/flexible/lifecycle/support-schedule#net). We recommend that you upgrade your app to use the [latest version of .NET](https://cloud.google.com/appengine/docs/flexible/dotnet/runtime#newversions).