Json Encoder/Decoder use new version of Newtonsoft.Json
As mentioned in the other comment, this was added in Feature Pack 2 for BizTalk 2016. Please comment further if this does not give the functionality you are requesting.
Niklas Gustafsson commented
Will this be added as CU to other versions of Biztalk (e.g. 2013, 2013R2)?
Coen aka Colin Dijkgraaf commented
Feature Pack 2 for BizTalk 2016 https://docs.microsoft.com/en-gb/biztalk/core/configure-the-feature-pack. Use latest Newtonsoft JSON
Newtonsoft is a JSON framework for .NET. In this feature pack, support for version 10.0.3 is included. Download v. 10.0.3 directly from NuGet.