Upgrading from 3.7.x

The 3.8 driver introduces a small but significant breaking change to the existing API for any application that already depends on session support (introduced in the 3.6 release to support causal consistency): the type of ClientSession changes from com.mongodb.session.ClientSession to com.mongodb.client.ClientSession. This is both source and binary incompatible with the 3.7 release. This change was required in order to introduce support in the driver for transactions that works in both the synchronous and the asynchronous drivers.

In addition, the default authSource value for connection strings with an authMechanism of PLAIN has changed from admin to $external. Users wishing to continue to use PLAIN authentication with the admin database should declare authSource=admin on the connection string.

Otherwise, the 3.8 release is binary and source compatible with the 3.7 release, except for methods that have been added to interfaces that have been marked as unstable, and changes to classes or interfaces that have been marked as internal or annotated as Beta.

Upgrading from 2.x

See the Upgrade guide in the 3.0 driver reference documentation for breaking changes in 3.0.

System Requirements

The minimum JVM is now Java 6: however, specific features require Java 7:

• SSL support requires Java 7 in order to perform host name verification, which is enabled by default. See SSL for details on how to disable host name verification.
• The asynchronous API requires Java 7, as by default it relies on AsynchronousSocketChannel for its implementation. See Async for details on configuring the driver to use Netty instead.

Compatibility

The following table specifies the compatibility of the MongoDB Java driver for use with a specific version of MongoDB.

The following table specifies the compatibility of the MongoDB Java driver for use with a specific version of Java.