-Added support for XML document type
-Changed string JValue with a null value to be written as null instead of empty string
-Fixed StringEnumConverter thread safety
-Changed serializing ISerializable types under partial trust to error to fix security issue
-Fixed LinqBridge collision error in .NET 2.0 by moving types to a different namespace
-Fixed JObject.Keys error when object has no items
-Added WriteObjectId to BsonWriter
-Added BsonObjectId and BsonObjectIdConverter classes
-Added KeyValuePairConverter
-Added DynamicCodeGeneration flag to DefaultContractResolver
-Changed JsonConverter.ReadJson to add an extra parameter: currentValue
-Changed class converter to be resolved from contract
-Changed built in converters to be resolved once when the contract is created. Big performance gain!
-Added BsonReader, BsonWriter
-Added support for reading and writing byte arrays to JsonReader, JsonWriter and LINQ to JSON classes
-Added ReadAsBytes to JsonReader
-Changed Silverlight build serializer to look for a TypeConverter
-Changed .NET build to not rely on System.ComponentModel.DataAnnotations assembly to support .NET 4.0 client profile
-Remove DateTimeOffset stand-in from Compact Framework build
-Fixed .NET 2.0 build to run on environments without .NET 2.0 SP1
-Fixed deserialization to always use a new value created from a JsonConverter
-Fixed XmlNodeConverter to support converting comments in JSON