@John Fox Thank you for reaching out
Azure Cosmos DB does not host the MongoDB database engine, it implements the wire protocol for MongoDB so that any compatible MongoDB client driver or SDK can connect, without special configuration.
Azure Cosmos DB API for MongoDB is compatible with the following MongoDB server versions:
Version 4.0
Version 3.6
Version 3.2
You can migrate your existing Mongo DB to Azure Cosmos DB Mongo API using Data Migration Service.
A detailed tutorial is here
Please let us know if you have any further questions and we would be happy to assist.
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