DotNet Provider is Dropping (pure) .NET 2.0 support and Switching to C# 5 compiler
Here is the full thread abou the C#5 switch and the reasoning for .NET 2.0 code drop is here
With transition to .NET 4.5 I’m considering dropping pure .NET FW 2.0 support. The .NET 2.0 runtime WILL BE still supported, but you’ll have to have all the updates ending in .NET 3.5 SP1 installed.