** Epic
* [PHPC-1075] - Import libbson and libmongoc Autotools configuration
* [PHPC-1086] - Improve exception hierarchy for RuntimeException
* [PHPC-1102] - PHPC MongoDB 4.0 Support

** New Feature
* [PHPC-314] - Implement type map syntax for documents within field paths
* [PHPC-578] - Expose result document for failed commands
* [PHPC-1076] - Expose result document for failed commands via CommandFailedEvent
* [PHPC-1087] - Introduce ServerException class
* [PHPC-1089] - Introduce CommandException class
* [PHPC-1105] - Implement SASLPrep
* [PHPC-1108] - SCRAM-SHA-256 Support
* [PHPC-1140] - Implement Transactions spec
* [PHPC-1153] - Handshake changes for SDAM and Auth
* [PHPC-1181] - Retryable writes should consider more errors retryable
* [PHPC-1211] - Create Int64 class to wrap 64-bit integers on 32-bit platforms

** Bug
* [PHPC-332] - Test that server selection throws ConnectionTimeoutException
* [PHPC-355] - Connection timeouts should throw ConnectionTimeoutException, and not RuntimeException
* [PHPC-1022] - Sporadic SCRAM-SHA-1 authentication failures due to "storedKey mismatch"
* [PHPC-1158] - Segfault during OpenSSL cleanup routines
* [PHPC-1166] - Update zend array recursion protection for PHP 7.3
* [PHPC-1169] - TLS renegotiation errors during heartbeat when using Secure Transport
* [PHPC-1195] - BulkWrite::update() should append arrayFilters option as array
* [PHPC-1196] - Raise client error if arrayFilters option is used when unsupported
* [PHPC-1198] - Ensure bundled libraries set CFLAGS correctly

** Task
* [PHPC-585] - Document maxTimeMS example for executeCommand and executeQuery
* [PHPC-759] - Ensure that the driver can be compiled as a built-in PHP extension
* [PHPC-1083] - Change "available" RP constant to use libmongoc's constant instead of hard coding it
* [PHPC-1088] - Deprecate SSLConnectionException
* [PHPC-1107] - Resync tests to update handling of inconsistent write concern
* [PHPC-1113] - Migrate tests to use a common URI environment variable
* [PHPC-1114] - Add template.rc file to embed the right MongoDB version in the Windows binary
* [PHPC-1118] - Create clang-format file and Makefile targets
* [PHPC-1121] - Test Windows builds on Appveyor
* [PHPC-1126] - Prohibit using unacknowledged writes with explicit sessions
* [PHPC-1132] - Remove HHVM checks in test suite
* [PHPC-1133] - Remove unused includes in SKIPIF and FILE sections
* [PHPC-1137] - Deprecate maxScan query option
* [PHPC-1138] - Deprecate snapshot option
* [PHPC-1143] - Select ServerException for MONGOC_ERROR_WRITE_CONCERN domain
* [PHPC-1144] - Use server-side error code for BulkWriteException
* [PHPC-1145] - Fix development build warnings for numeric type conversions
* [PHPC-1148] - Throw InvalidArgumentException if BulkWrite is executed multiple times
* [PHPC-1160] - Initialize bson_error_t structs to zero
* [PHPC-1174] - Upgrade bundled libbson and libmongoc to 1.10
* [PHPC-1185] - Remove support for Cyrus SASL search path
* [PHPC-1186] - Consolidate libbson and libmongoc build configs
* [PHPC-1188] - Use --coverage compiler/linker option for code coverage builds
* [PHPC-1191] - Don't allow coverage for static builds
* [PHPC-1193] - Upgrade bundled libbson and libmongoc to 1.11

** Improvement
* [PHPC-850] - Add var_export() support for ReadConcern, ReadPreference, and WriteConcern
* [PHPC-922] - Improve specificity in generic corrupt BSON exception message
* [PHPC-1090] - Clean up switch statements for exception class selection
* [PHPC-1091] - Ensure ExecutionTimeoutException selection only considers server error code
* [PHPC-1120] - Decrease likelihood of implicit session leaks
* [PHPC-1127] - Remove old Mongo Orchestration cluster tests
* [PHPC-1139] - Update algorithm for Kerberos hostname canonicalization
* [PHPC-1149] - php_phongo_dispatch_handlers() should break if exception is thrown
* [PHPC-1154] - Implement wild card syntax for typemap field paths
* [PHPC-1189] - Prefix maintainer/coverage configure options with "mongodb"
* [PHPC-1200] - Remove MD5 from ObjectID generation
* [PHPC-1216] - Always validate and apply wtimeoutMS in URI options array