IEnumerable<T> was in the 2.0 release - it's generic, there were no generics in 1.0 But the non-generic IEnumerable and foreach syntax was in from 1.0 https://

IEnumerable<T> was in the 2.0 release - it's generic, there were no generics in 1.0 But the non-generic IEnumerable and foreach syntax was in from 1.0 https://docs.microsoft.com/en-us/dotnet/api/system.collections.ienumerable https://docs.microsoft.com/en-us/dotnet/api/system.collectio... "Yield return" generators is also from 2.0