This is a preview release of the next feature release of the Ruby MongoDB driver.

This release includes the following new features:

• RUBY-2130 Move the query cache into the driver and improve implementation
• RUBY-2093 Non-stapled OCSP Support

The following non-breaking changes were made:

• RUBY-2299 Support per-operation write concern for database and collection write methods
• RUBY-1632 Handle bogus/invalid read concern sub-options
• RUBY-2356 Set default logger level to info
• RUBY-2357 Standardize on STDOUT over $stdout
• RUBY-2289 Display monitoring state in client summary
• RUBY-1932 Specify timeouts for DNS queries for SRV URIs
• RUBY-2346 Tag names are downcased when given in URI options
• RUBY-2421 Auth mechanism properties not downcased when client is created with host and Ruby options with symbol key
• RUBY-2166 Mark servers unknown when connections experience network errors during setup
• RUBY-2020 Set explain verbosity from Mongo::Collection::View::Explainable
• RUBY-2387 Mark operation result as a public API

The following bugs were fixed:

• RUBY-2345 Validate document size on pre-3.6 servers

Support for Ruby versions 2.3 and 2.4 has been deprecated in this release. Read more about this change here.