breaking-changes-to-database-engine-features-in-sql-server-2017.md

title	Breaking Changes to Database Engine Features in SQL Server 2017 | Microsoft Docs
description	Breaking changes to Database Engine Features in SQL Server 2017
ms.date	04/19/2017
ms.prod	sql-vnext
ms.reviewer
ms.suite
ms.technology	database-engine
ms.tgt_pltfrm
ms.topic	article
helpviewer_keywords	breaking changes 2017 [SQL Server]
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caps.latest.revision	1
author	BYHAM
ms.author	rickbyh
manager	jhubbard

Breaking Changes to Database Engine Features in [!INCLUDEsssqlv14-md]

[!INCLUDEtsql-appliesto-ssvnxt-xxxx-xxxx-xxx]

This topic describes breaking changes in the [!INCLUDEsssqlv14-md][!INCLUDEssDE]. These changes might break applications, scripts, or functionalities that are based on earlier versions of [!INCLUDEssNoVersion]. You might encounter these issues when you upgrade.

Breaking Changes in [!INCLUDEsssqlv14-md][!INCLUDEssDE]

• CLR uses Code Access Security (CAS) in the .NET Framework, which has been marked as obsolete. Beginning with [!INCLUDEsssqlv14-md][!INCLUDEssDE], an sp_configure option called clr strict security is introduced to enhance the security of CLR assemblies. clr strict security is enabled by default, and treats SAFE and EXTERNAL_ACCESS CLR assemblies as if they were marked UNSAFE. The clr strict security option can be disabled for backward compatibility, but this is not recommended. When clr strict security is disabled, a CLR assembly created with PERMISSION_SET = SAFE may be able to access external system resources, call unmanaged code, and acquire sysadmin privileges. For more information, see clr strict security.

Previous Versions

• Breaking Changes to Database Engine Features in SQL Server 2016

• Breaking Changes to Database Engine Features in SQL Server 2014

• Breaking Changes to Database Engine Features in SQL Server 2012

• Breaking Changes to Database Engine Features in SQL Server 2008

See Also

Deprecated Database Engine Features in SQL Server 2016
Discontinued Database Engine Functionality in SQL Server 2016
SQL Server Database Engine Backward Compatibility
ALTER DATABASE Compatibility Level (Transact-SQL)