As explained earlier at this blog post, we improved how the GET Properties endpoint returns data. And added a new forceget query string parameter to return the JSON even if the size is bigger than 20Mb. Now this s available on the packages.
For .NET package version 1.4.0 you can simply call the endpoints, like before, no change required. No breaking change on your code.
For Nodejs package version 0.4.4, use the options parameter like:
derivativesApi.getModelviewProperties(urn, guid, {'forceget': true}, oauthClient, token)