MongoDB developers want the flexibility to build applications their way – and on the stable MongoDB version they choose.

Azure Cosmos DB API for MongoDB 4.0 was recently released, but what if you’re happy running 3.6 and don’t have the time or ability to upgrade? Some companies are retiring MongoDB 3.6, but you can keep your existing 3.6 and 3.2 deployments running in production with Azure Cosmos DB! There are no plans to retire our supported versions.

With Azure Cosmos DB API for Mongo DB, there’s no need to upgrade simply to prevent your version from reaching end-of-life (EOL). Azure Cosmos DB API for MongoDB 3.6 and 3.2 continue to live on for all use cases.

A single codebase

Databases such as MongoDB typically run on separate codebases for each version. Doing so reduces the complexity of development, but adds the complexity of maintenance for each version after its release. With Azure Cosmos DB API for MongoDB, all server versions share the same codebase! New features all live within the same codebase and are turned on or off based on feature flags controlled by the server version your account is set to. This is why upgrading or downgrading your Azure Cosmos DB API account can be completed in seconds with zero downtime.

Version dependent features

When connecting to your Azure Cosmos DB API for MongoDB database account, your client is provided a server version for the database it’s connecting to. Based on that server version, your client knows which features should be available to it. For example, if the server responds with version 4.0, your client knows that multi-document transactions are supported.

Some features, such as wildcard indexes, aren’t constrained by the server version the client receives. This allows us to introduce powerful functionality that was introduced in later MongoDB versions in our older versions, giving you the benefit of these features with no database version upgrades!

This architecture is unique to Azure Cosmos DB API for MongoDB and gives you the benefit of choosing and staying on the version that works best for you.

Going forward

None of Azure Cosmos DB API for MongoDB versions have had end-of-life EOL announced for them, and our policy requires a three-year notice for any future EOL. With Azure Cosmos DB API for MongoDB, your favorite MongoDB server version lives on, giving you the power to choose which version you want to use.

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