This is the first stable release in the mongocxx 3.4 series.

This release provides support for new features MongoDB 4.0 (most notably transactions) as well as command monitoring and SDAM monitoring.

Please note that this version of mongocxx requires the MongoDB C driver 1.13.0.

See the MongoDB C++ Driver Manual and the Driver Installation Instructions for more details on downloading, installing, and using this driver.

NOTE: The mongocxx 3.4.x series does not promise API or ABI stability across patch releases.

Here is the full list of user-visible issues that have been resolved in 3.4.0 since the prior 3.3 series:

New Feature

• [CXX-1385] - Add API for subscribing to SDAM events
• [CXX-1386] - Implement command monitoring API
• [CXX-1433] - Implement Database Enumeration spec
• [CXX-1478] - Support ReplaceOptions in CRUD API
• [CXX-1505] - Implement SASLPrep
• [CXX-1509] - SCRAM-SHA-256 Support
• [CXX-1531] - Implement Transactions spec
• [CXX-1538] - Delete public bulk_write constructor
• [CXX-1541] - Handshake changes for SDAM and Auth
• [CXX-1558] - Remove collection::bulk_write(bulk_write&)
• [CXX-1559] - Update SCRAM-SHA-256 implementation and tests for spec change
• [CXX-1582] - Support nameOnly option in listCollections command
• [CXX-1584] - Add helpers and options for Change Streams Follow-on Work
• [CXX-1585] - Remove MD5 from ObjectID generation
• [CXX-1592] - Add MongoDB 4.0 to the Evergreen matrix
• [CXX-1594] - Implement new count API
• [CXX-1616] - Remove equality/inequality operators from options classes
• [CXX-1622] - Test only the initial command in a transaction includes readConcern
• [CXX-1639] - Support new readConcern level "available"
• [CXX-1658] - Generate C Driver version number when installing

Bug

• [CXX-1595] - GNU 4.9.3: 'max_align_t' was not declared
• [CXX-1625] - Android NDK r17 compiler error
• [CXX-1626] - CRUD operations set ordered to false by default
• [CXX-1638] - Don't call string_view::to_string

Improvement

• [CXX-1499] - Don't access bson_iter_t internals
• [CXX-1500] - document::view::find should use bson_iter...w_len functions
• [CXX-1528] - Deprecate snapshot option
• [CXX-1562] - Port session tests to mongocxx command monitoring API
• [CXX-1573] - Spec tests should use the same format for bulk writes
• [CXX-1577] - Flexible collection creation
• [CXX-1578] - Remove options::aggregate::use_cursor
• [CXX-1580] - Log backtraces in test failures on Evergreen
• [CXX-1586] - Add user commands to list of commands that write
• [CXX-1591] - Only send bypassDocumentValidation if it's true
• [CXX-1596] - Use mongoc_cursor_new_from_command_reply_with_opts
• [CXX-1601] - Update ChangeStream spec to detail usage of startAtOperationTime
• [CXX-1620] - Migrate from functions deprecated in libmongoc 1.12
• [CXX-1651] - Rewrite "Contributing" page
• [CXX-1653] - Remove database::modify_collection
• [CXX-1657] - Require libbson and libmongoc 1.13.0
• [CXX-1660] - Fix doxygen warnings
• [CXX-1666] - improve documentation of element::bool()