Accouding to Official Amazon DocumentDB homepage, the cloud services only two versions which are 3.6 and 4.0.
But is it possible to use 4.0.28 version or another 4.X version? I couldn't find the information exactly!
I tried to search official documents of Amazon DocumentDBs and I want to expect to use MongoDB 4.0.28 at least!
Amazon DocumentDB is compatible with 3.6 and 4.0. It is required that you use a MongoDB driver or utility that is compatible with MongoDB 4.0 or higher. ( for MongoDB 4.0.x compatibility) You can verify the compatibility of your application (3.6, 4.0 or higher) with Amazon DocumentDB using the following DocumentDB compatibility tool : https://github.com/awslabs/amazon-documentdb-tools/tree/master/compat-tool