Customer developers use MongoDB 3.6 inside a docker container which is derived from an image with standalone configuration.  They are upgrading their Java web services to use sessions.  This entails switching from using legacy APIs to new APIs found in the Uber driver 3.12.4.  When they run their automated unit tests they receive the error...

com.mongodb.MongoClientException: Sessions are not supported by the MongoDB cluster to which this client is connected

They are concerned they need to change their DevOps flows to accommodate new MongoDB features, such as sessions.  Discussions with jeff.yemin@gmail.com on Slack indicate a standalone db supports sessions (but with limited functionality).  The driver, on the other hand, blocks the interaction.