This is with gnome-do-plugins 0.8.2.1 and libgoogle-data-mono 1.6.0.0 and mono 2.6.7:
Compiling GoogleContacts.dll...
./src/GMailClient.cs(54,45): warning CS0618: `System.Net.ServicePointManager.CertificatePolicy' is obsolete: `Use ServerCertificateValidationCallback instead'
./src/GMailClient.cs(66,31): warning CS0618: `Google.GData.Client.FeedQuery.UseSSL' is obsolete: `This is deprecated and replaced by UseSSL on the service and the requestsettings'
./src/GMailClient.cs(80,41): error CS0309: The type `Google.GData.Extensions.StructuredPostalAddress' must be convertible to `Google.GData.Extensions.CommonAttributesElement' in order to use it as parameter `T' in the generic type or method `GMail.GMailClient.AddDetails<T>(Do.Universe.ContactItem, Google.GData.Extensions.ExtensionCollection<T>)'
./src/GMailClient.cs(93,22): (Location of the symbol related to previous error)
/usr/lib/mono/gac/Google.GData.Extensions/1.6.0.0__0b4c5df2ebf20876/Google.GData.Extensions.dll (Location of the symbol related to previous error)
./src/GMailClient.cs(127,59): warning CS0618: `Google.GData.Extensions.PostalAddress' is obsolete: `Use New Version StructuredPostalAddress'
Compilation failed: 1 error(s), 3 warnings
