I suspect Cosmos only support 3.x MongoDb API because later API versions are under license. AWS DocumentDb has the same problem.
I'm surprised with that many limitations of CosmosDb after multiple years of development
Thank you Gleb!
You're right about MongoDB - they changed licensing 1.5 years ago (I didn't know about that).
MS dev teams usually aren't highly productive. Perhaps they so big that simply get bogged in internal bureaucracy. Another example could be MS SQL Server vs PostgreSQL, where the later outperformed SQL Server on many dimensions. Marketing, on the other side, is pretty good usually.
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