The Chilkat .NET download for the 2.0 .NET Framework is also compatible with the 3.5 Framework.
The .NET 3.* Framework represents a superset of the .NET 2.0 runtime. Programs that use .NET 3.* will be able to use the existing Chilkat .NET 2.0 components.
More information about 3.0 / 3.5 .NET Framework compatibility.