Changes
[Added]
- Support for PHP 7.4
- Support for [Microsoft ODBC Driver 17.5](
https://docs.microsoft.com/sql/connect/odbc/download-odbc-driver-for-sql-server?view=sql-server-ver15) on all platforms
- Support for Debian 10 and Red Hat 8 - require MS ODBC Driver 17.4+
- Support for macOS Catalina, Alpine Linux 3.11 and Ubuntu 19.10 - require ODBC Driver 17.5+
- Feature Request [#929](https://github.com/microsoft/msphpsql/issues/929) - new [Language option](https://github.com/microsoft/msphpsql/wiki/Features#language) - Pull Request [#930](https://github.com/microsoft/msphpsql/pull/930)
- [Data Classification Sensitivity Metadata Retrieval](https://github.com/microsoft/msphpsql/wiki/Features#data-classification-sensitivity-metadata) - requires ODBC Driver 17.4.2+ and [SQL Server 2019](https://www.microsoft.com/sql-server/sql-server-2019)
- Feature Request [#1018](https://github.com/microsoft/msphpsql/issues/1018) - support for [PHP extended string types](https://github.com/microsoft/msphpsql/wiki/Features#natlTypes) - Pull Request [#1043](https://github.com/microsoft/msphpsql/pull/1043)
- [Always Encrypted with secure enclaves](https://github.com/microsoft/msphpsql/wiki/Features#alwaysencryptedV2) - requires ODBC Driver 17.4+ and [SQL Server 2019](https://www.microsoft.com/sql-server/sql-server-2019)
- Feature Request [#1063](https://github.com/microsoft/msphpsql/issues/1063) - add configurable options for locale settings in Linux and macOS - Pull Request [#1069](https://github.com/microsoft/msphpsql/pull/1069)
[Removed]
- Dropped support for [PHP 7.1](https://www.php.net/supported-versions.php)
- Dropped support for SQL Server 2008 R2, macOS Sierra, Ubuntu 18.10 and Ubuntu 19.04.
[Fixed]
- Pull Request [#972](https://github.com/microsoft/msphpsql/pull/972) - Removed redundant calls to retrieve the number of columns or rows in the current query result set
- Pull Request [#978](https://github.com/microsoft/msphpsql/pull/978) - PDO_SQLSRV implementation of PDO::getColumnMeta now references cached metadata rather than making an ODBC call every time
- Pull Request [#979](https://github.com/microsoft/msphpsql/pull/979) - Added support for Data Classification Sensitivity metadata retrieval
- Pull Request [#985](https://github.com/microsoft/msphpsql/pull/985) - Fixed memory issues with Data Classification data structures
- Issue [#432](https://github.com/microsoft/msphpsql/issues/432) - Having any invalid UTF-8 name in the connection string will no longer invoke misleading error messages
- Issue [#909](https://github.com/microsoft/msphpsql/issues/909) - Fixed potential exception with locale issues in macOS
- Pull Request [#992](https://github.com/microsoft/msphpsql/pull/992) - Produced the correct error when requesting Data Classification metadata with ODBC drivers prior to 17
- Pull Request [#1001](https://github.com/microsoft/msphpsql/pull/1001) - Fixed compilation issue with PHP 7.4 alpha
- Pull Request [#1004](https://github.com/microsoft/msphpsql/pull/1004) - Fixed another compilation issue with PHP 7.4 alpha
- Pull Request [#1008](https://github.com/microsoft/msphpsql/pull/1008) - Improved data caching when fetching datetime objects
- Pull Request [#1011](https://github.com/microsoft/msphpsql/pull/1011) - Fixed a potential buffer overflow when parsing for escaped braces in the connection string
- Pull Request [#1015](https://github.com/microsoft/msphpsql/pull/1015) - Fixed compilation issues and addressed various memory leaks detected by PHP 7.4 beta 1
- Issue [#1027](https://github.com/microsoft/msphpsql/issues/1027) - Fixed how drivers handle query timeout settings
- Pull Request [#1049](https://github.com/microsoft/msphpsql/pull/1049) - Performance improvement for fetching from tables with many columns - cached the derived php types with column metadata to streamline data retrieval
- Pull Request [#1068](https://github.com/microsoft/msphpsql/pull/1068) - Some cosmetic changes to source code as per suggestions from a static analysis tool
- Issue [#1079](https://github.com/microsoft/msphpsql/issues/1079) - Support sql_variant types when using client buffers
[Limitations]
- No support for inout / output params when using sql_variant type
- No support for inout / output params when formatting decimal values
- In Linux and macOS, setlocale() only takes effect if it is invoked before the first connection. Attempting to set the locale after connecting will not work
- Always Encrypted requires [MS ODBC Driver 17+](https://docs.microsoft.com/sql/connect/odbc/linux-mac/installing-the-microsoft-odbc-driver-for-sql-server)
- Only Windows Certificate Store and Azure Key Vault are supported. Custom Keystores are not yet supported
- Issue [#716](https://github.com/Microsoft/msphpsql/issues/716) - With Always Encrypted enabled, named parameters in subqueries are not supported
- Issue [#1050](https://github.com/microsoft/msphpsql/issues/1050) - With Always Encrypted enabled, insertion requires the column list for any tables with identity columns
- [Always Encrypted limitations](https://docs.microsoft.com/sql/connect/php/using-always-encrypted-php-drivers#limitations-of-the-php-drivers-when-using-always-encrypted)
[Known Issues]
- In Alpine Linux, the Client-Side Cursors feature may cause an access violation if both sqlsrv and pdo_sqlsrv are enabled. Either enable only sqlsrv or pdo_sqlsrv, or build PHP from source by compiling the drivers statically.
- Connection pooling on Linux or macOS is not recommended with [unixODBC](http://www.unixodbc.org/) < 2.3.7
- When pooling is enabled in Linux or macOS
- unixODBC <= 2.3.4 (Linux and macOS) might not return proper diagnostic information, such as error messages, warnings and informative messages
- due to this unixODBC bug, fetch large data (such as xml, binary) as streams as a workaround. See the examples [here](https://github.com/Microsoft/msphpsql/wiki/Features#pooling)