Version 1.6.0

** Bug**

• [PHPC-1331] - Fix typos in ReadPreference::__set_state() errors
• [PHPC-1332] - PHP array API downcasts 64-bit integers to 32-bit values on Windows
• [PHPC-1341] - Remove XFAIL for unacknowledged write concern test
• [PHPC-1419] - Error label from server error is not exposed in ServerException
• [PHPC-1432] - Fix documentation for Session::startTransaction() options parameter
• [PHPC-1435] - Fix Session::startTransaction() arginfo

** Epic**

• [PHPC-837] - Update PHP driver to test in Evergreen
• [PHPC-1112] - Test suite improvements
• [PHPC-1233] - FY2019Q3 Quick Wins
• [PHPC-1235] - PHPC MongoDB 4.2 Support
• [PHPC-1329] - Fix Windows build failures on AppVeyor

** New Feature**

• [PHPC-1123] - Create interface for Cursor class
• [PHPC-1222] - Implement accessor for error labels on exception classes
• [PHPC-1231] - Add Session::isInTransaction to indicate whether a transaction is active
• [PHPC-1254] - Implement ObjectID spec
• [PHPC-1288] - Implement Unified URI Options
• [PHPC-1290] - Support mongos pinning for sharded transactions
• [PHPC-1291] - Retryable Reads
• [PHPC-1292] - Support polling SRV records for mongos discovery
• [PHPC-1297] - Support sharded transactions recovery token
• [PHPC-1319] - Drivers should use majority write concern when retrying commitTransaction
• [PHPC-1324] - Support Retryable Writes on by Default
• [PHPC-1355] - Add the ability to specify a pipeline to an update command
• [PHPC-1371] - Drivers send recoveryToken on abortTransaction
• [PHPC-1382] - Allow applications to set maxTimeMS for commitTransaction

** Task**

• [PHPC-691] - Test that Server command/query execute methods send read preference to mongos
• [PHPC-857] - Create Evergreen matrix for various test configurations
• [PHPC-858] - Add authentication axis to Evergreen matrix
• [PHPC-859] - Add SSL axis to Evergreen matrix
• [PHPC-860] - Add PHP runtime axis to Evergreen matrix
• [PHPC-861] - Add MongoDB version axis to Evergreen matrix
• [PHPC-862] - Add Evergreen matrix to run against nightly server builds
• [PHPC-863] - Add RHEL 7.1/Power 8 to the operating system axis
• [PHPC-864] - Add storage engines to Evergreen matrix
• [PHPC-1122] - Check whether we still need SUPPRESS_UNUSED_WARNING
• [PHPC-1173] - Reimplement replica set seedlist tests
• [PHPC-1180] - Fix peer certificate verification errors for SSL clusters
• [PHPC-1219] - Relax requirement for replica set tagsets assertions
• [PHPC-1240] - Remove noprealloc, nssize and smallfiles from MO configurations
• [PHPC-1250] - Document the order in which skip_ifs in tests need to be done
• [PHPC-1271] - Add (only) RHEL on zSeries to Evergreen Matrix
• [PHPC-1275] - Bump wire protocol version for 4.2
• [PHPC-1276] - Create tool chain for PHP binaries
• [PHPC-1299] - Add Ubuntu 16.04/ARM64 to the operating system axis
• [PHPC-1320] - Regenerate test certificates with SHA256 signatures
• [PHPC-1333] - Revert to virtualized Travis CI environments
• [PHPC-1345] - Revise fragile session ID assertions
• [PHPC-1364] - Upgrade libmongoc to 1.14.0
• [PHPC-1369] - Upgrade libmongoc to 1.15.0
• [PHPC-1370] - Revise test assertion for unknown modifier error message
• [PHPC-1377] - Remove support for PHP 5.5
• [PHPC-1390] - Remove 7.0 and add 7.3 on AppVeyor
• [PHPC-1392] - Avoid spurious failure in ConnectionTimeoutException test due to slow auth
• [PHPC-1399] - Test MongoDB 4.2 in Evergreen
• [PHPC-1412] - Fix test failures when retryable writes are enabled
• [PHPC-1413] - Fix test failures executing insert on secondary
• [PHPC-1414] - Skip tests when mongo orchestration is not available
• [PHPC-1415] - Fix test failures for sharded cluster without replica set
• [PHPC-1428] - Bump libmongoc to 1.15.1

** Improvement**

• [PHPC-1206] - Add __set_state() support for ReadConcern, ReadPreference, and WriteConcern
• [PHPC-1229] - Populate error labels for bulk write exceptions
• [PHPC-1301] - php_phongo_cursor_t.got_iterator should use bool type
• [PHPC-1307] - Exception interface should extend Throwable on PHP 7+
• [PHPC-1346] - Do not allow empty string for username
• [PHPC-1373] - WriteResult is inaccessible if executeBulkWrite() encounters socket error
• [PHPC-1394] - Don't send $readPreference to standalone servers
• [PHPC-1422] - Raise an actionable error message when retryWrites fails due to using an unsupported storage engine
• [PHPC-1431] - Session::startTransaction() should accept null for options