** Bug
* [PHPC-2013] - RHEL 7.0 and 7.1 builds fail due to incompatible pointer warnings
* [PHPC-2020] - Validate loadBalanced URI array option

** Epic
* [PHPC-1150] - Support SDAM Monitoring

** New Feature
* [PHPC-1805] - Implement ServerDescription class
* [PHPC-1891] - Implement TopologyDescription class
* [PHPC-1892] - Define SDAMSubscriber interface
* [PHPC-1893] - Define SDAM event classes
* [PHPC-1900] - Allow custom service names with srvServiceName URI option
* [PHPC-1908] - Allow limiting mongos servers with srvMaxHosts option

** Task
* [PHPC-1342] - Add documentation warning against the use of duplicate key names
* [PHPC-1909] - Set minWireVersion to 6 (MongoDB 3.6)
* [PHPC-1953] - Create tests for event object debug handlers
* [PHPC-1958] - Ensure that getTopologyId() gives the same result for all SDAM events
* [PHPC-1959] - Change SDAM event tests to use Manager::addSubscriber()
* [PHPC-1973] - Bump maxWireVersion to 14 for MongoDB 5.1
* [PHPC-2008] - writeresult-getserver-002 fails to drop collection in local db on replicaset-auth
* [PHPC-2012] - Remove extra AX_CHECK_COMPILE_FLAG args
* [PHPC-2019] - Remove Solaris checks in m4 build scripts
* [PHPC-2022] - Use mongoc_host_list in event structs
* [PHPC-2023] - Allow observation of TopologyClosedEvent
* [PHPC-2028] - Replace PHONGO_ALLOC_OBJECT_T macro with zend_object_alloc
* [PHPC-2031] - Upgrade libmongoc to 1.21.1 and libmongocrypt to 1.3.2
* [PHPC-2034] - Bump maxWireVersion for MongoDB 5.2
* [PHPC-2036] - Remove outdated prose test in causal consistency spec
* [PHPC-2037] - Remove vim modeline comments
* [PHPC-2038] - Initialize zval in phongo_clientencryption_init
* [PHPC-2039] - Remove disabled debugging code in bson.c
* [PHPC-2040] - Break down php_phongo.c into smaller files
* [PHPC-2042] - Remove conditional win32/time.h include in UTCDateTime.c
* [PHPC-2047] - Update load balancer tests to support dedicated load balancer port
* [PHPC-2073] - Remove test environments and checks for pre-3.6 server versions
* [PHPC-2074] - Clarify in contributing docs that mongo-orchestration is not required to run tests

** Improvement
* [PHPC-1647] - Defer to libmongoc for cross-option URI validation
* [PHPC-1910] - Implement Server::getServerDescription
* [PHPC-1925] - ServerDescription::getType() should return a string
* [PHPC-1934] - Check for uninitialized intern in ServerDescription get_properties_hash
* [PHPC-1950] - Lift restriction on authSource without credentials when set in URI options array
* [PHPC-2003] - Expose whether a client session is dirty
* [PHPC-2025] - Support load balancer in ServerDescription and TopologyDescription
* [PHPC-2026] - Warn if ServerDescription::getLastUpdateTime() must be truncated
* [PHPC-2030] - Allow observation of commands issued during mongoc_client_destroy()
* [PHPC-2032] - Report more concise debug info for ended sessions