Add 6.0.2 context to 7.0.0-P1 Release Notes

release-notes/7.0/7.0.0-preview1.md

@@ -2,6 +2,8 @@
 
 ## Preview Release 7.0.0-preview1.25257.1 - 2025-09-12
 
+## Changes Since [6.1.0](../6.1/6.1.0.md)
+
 This update brings the following changes since the [6.1.0](../6.1/6.1.0.md)
 release:
 
@@ -62,6 +64,219 @@ release:
 - Updated `Azure.Identity` dependency to v1.14.2.
   ([#3538](https://github.com/dotnet/SqlClient/pull/3538))
 
+## Changes Since [6.0.2](../6.0/6.0.2.md)
+
+This update brings the following changes since the [6.0.2](../6.0/6.0.2.md)
+release.  Changes already noted above are omitted:
+
+### Additions
+
+#### Added dedicated SQL Server vector datatype support
+
+*What Changed:*
+
+- Optimized vector communications between MDS and SQL Server 2025, employing a
+  custom binary format over the TDS protocol.
+  ([#3433](https://github.com/dotnet/SqlClient/pull/3433),
+   [#3443](https://github.com/dotnet/SqlClient/pull/3443))
+- Reduced processing load compared to existing JSON-based vector support.
+- Initial support for 32-bit single-precision floating point vectors.
+
+*Who Benefits:*
+
+- Applications moving large vector data sets will see beneficial improvements
+  to processing times and memory requirements.
+- Vector-specific APIs are ready to support future numeric representations with
+  a consistent look-and-feel.
+
+*Impact:*
+
+- Reduced transmission and processing times for vector operations versus JSON
+  using SQL Server 2025 preview:
+  - Reads:  50x improvement
+  - Writes: 3.3x improvement
+  - Bulk Copy: 19x improvement
+  - (Observed with vector column of max 1998 size, and 10,000 records for each
+    operation.)
+- Improved memory footprint due to the elimination of JSON
+  serialization/deserialization and string representation bloat.
+- For backwards compatibility with earlier SQL Server Vector implementations,
+  applications may continue to use JSON strings to send/receive vector data,
+  although they will not see any of the performance improvements noted above.
+
+#### Revived .NET Standard 2.0 target support
+
+*What Changed:*
+
+- Support for targeting .NET Standard 2.0 has returned.
+  ([#3381](https://github.com/dotnet/SqlClient/pull/3381))
+- Support had previously been removed in the 6.0 release, with the
+  [community voicing concerns](https://github.com/dotnet/SqlClient/discussions/3115).
+
+*Who Benefits:*
+
+- Libraries that depend on MDS may seamlessly target any of the following
+  frameworks:
+  - .NET Standard 2.0
+  - .NET Framework 4.6.2 and above
+  - .NET 8.0
+  - .NET 9.0
+- Applications should continue to target runtimes.
+  - The MDS .NET Standard 2.0 target framework support does not include an
+    actual implementation, and cannot be used with a runtime.
+  - An application's build/publish process should always pick the appropriate
+    MDS .NET/.NET Framework runtime implementation.
+  - Custom build/publish actions that incorrectly try to deploy the MDS .NET
+    Standard 2.0 reference DLL at runtime are not supported.
+
+*Impact:*
+
+- Libraries targeting .NET Standard 2.0 will no longer receive warnings like
+  this:
+  - `warning NU1701: Package 'Microsoft.Data.SqlClient 6.0.2' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8, .NETFramework,Version=v4.8.1' instead of the project target framework '.NETStandard,Version=v2.0'. This package may not be fully compatible with your project.`
+
+#### Other Additions
+
+- Added packet multiplexing support to improve large data read performance.
+  ([#2714](https://github.com/dotnet/SqlClient/pull/2714),
+   [#3161](https://github.com/dotnet/SqlClient/pull/3161),
+   [#3202](https://github.com/dotnet/SqlClient/pull/3202))
+- Added support for special casing with Fabric endpoints.
+  ([#3084](https://github.com/dotnet/SqlClient/pull/3084))
+
+### Fixed
+
+- Fixed distributed transactions to be preserved during pooled connection resets.
+  ([#3019](https://github.com/dotnet/SqlClient/pull/3019))
+- Fixed application crash when the `Data Source` parameter begins with a comma.
+  ([#3250](https://github.com/dotnet/SqlClient/pull/3250))
+- Resolved synonym count discrepancies in debug mode.
+  ([#3098](https://github.com/dotnet/SqlClient/pull/3098))
+- Addressed warnings for down-level SSL/TLS versions.
+  ([#3126](https://github.com/dotnet/SqlClient/pull/3126))
+- Fixed missing <NeutralLanguage> property.
+  ([#3325](https://github.com/dotnet/SqlClient/pull/3325))
+- Fixed injection of UTF-8 BOM during bulk copy.
+  ([#3399](https://github.com/dotnet/SqlClient/pull/3399))
+- Fixed `SqlCachedBuffer` async read edge case.
+  ([#3329](https://github.com/dotnet/SqlClient/pull/3329))
+- Fixed `SqlSequentialTextReader` edge case with single-byte reads.
+  ([#3383](https://github.com/dotnet/SqlClient/pull/3383))
+- Fixed an incorrect error message when parsing connection string `PoolBlockingPeriod`.
+  ([#3411](https://github.com/dotnet/SqlClient/pull/3411))
+- Added missing `ToString()` override to `SqlJson`.
+  ([#3427](https://github.com/dotnet/SqlClient/pull/3427))
+- Fixed missing socket error codes on non-Windows platforms.
+  ([#3475](https://github.com/dotnet/SqlClient/pull/3475))
+- Fixed primary/secondary server SPN handling during SSPI negotiation.
+  ([#3478](https://github.com/dotnet/SqlClient/pull/3478))
+- Fixed AzureKeyVaultProvider package key caching to serialize Azure key fetch
+  operations.
+  ([#3477](https://github.com/dotnet/SqlClient/pull/3477))
+- Fixed a rare error related to multi-packet async text reads.
+  ([#3474](https://github.com/dotnet/SqlClient/pull/3474))
+- Fixed some spelling errors in the API docs.
+  ([#3500](https://github.com/dotnet/SqlClient/pull/3500))
+- Fixed a rare multi-packet string corruption bug.
+  ([#3513](https://github.com/dotnet/SqlClient/pull/3513))
+
+### Changed
+
+#### SqlDecimal type workarounds conversions
+
+*What Changed:*
+
+- Changed how SqlDecimal type workarounds perform conversions to meet
+  compliance policies.
+  ([#3467](https://github.com/dotnet/SqlClient/pull/3467))
+
+*Who Benefits:*
+
+- Microsoft products must not use undocumented APIs on other Microsoft products.
+  This change removes calls to undocumented APIs and replaces them with
+  compliant API use.
+
+*Impact:*
+
+- These changes impose an observed 5% decrease in performance on .NET Framework.
+
+#### SqlVector API improvements (since [6.1.0-preview2](6.1.0-preview2.md))
+
+*What Changed:*
+
+- Several changes were made to the SqlVector API published in the
+  [6.1.0-preview2](6.1.0-preview2.md) release
+  ([#3472](https://github.com/dotnet/SqlClient/pull/3472)):
+  - The SqlVector class was changed to a readonly struct.
+  - The null value constructor was changed to a static `CreateNull()` method.
+  - The `Size` property was removed.
+
+*Who Benefits:*
+
+- SqlVector instances gain the efficiencies of struct handling.
+
+*Impact:*
+
+- Early-adopter applications may require updates if they rely on the old APIs
+  and any class-specific behaviour.
+
+#### Other Changes
+
+- Reduced allocations when opening a connection.
+  ([#3364](https://github.com/dotnet/SqlClient/pull/3364))
+- Various performance improvements related to TDS parsing.
+  ([#3337](https://github.com/dotnet/SqlClient/pull/3337),
+   [#3377](https://github.com/dotnet/SqlClient/pull/3377),
+   [#3422](https://github.com/dotnet/SqlClient/pull/3422))
+- Improved native AOT support.
+  ([#3364](https://github.com/dotnet/SqlClient/pull/3364),
+   [#3369](https://github.com/dotnet/SqlClient/pull/3369),
+   [#3401](https://github.com/dotnet/SqlClient/pull/3401))
+- Progress towards [SSPI extensibility](https://github.com/dotnet/SqlClient/issues/2253).
+  ([#2454](https://github.com/dotnet/SqlClient/pull/2454))
+- Progress towards [connection pooling improvements](https://github.com/dotnet/SqlClient/issues/3356).
+  ([#3352](https://github.com/dotnet/SqlClient/pull/3352),
+   [#3396](https://github.com/dotnet/SqlClient/pull/3396))
+- Expanded/clarified SqlConnection's
+  [AccessToken](https://learn.microsoft.com/en-us/dotnet/api/microsoft.data.sqlclient.sqlconnection.accesstoken) and
+  [AccessTokenCallback](https://learn.microsoft.com/en-us/dotnet/api/microsoft.data.sqlclient.sqlconnection.accesstokencallback)
+  documentation.
+  ([#3339](https://github.com/dotnet/SqlClient/pull/3339))
+- Fixed some poorly formatted tables in the API docs.
+  ([#3391](https://github.com/dotnet/SqlClient/pull/3391))
+- Optimized binary size for AOT.
+  ([#3091](https://github.com/dotnet/SqlClient/pull/3091))
+- Refined bulk copy operations to handle unmatched column names more effectively.
+  ([#3205](https://github.com/dotnet/SqlClient/pull/3205))
+- Enhanced `SqlBulkCopy` to explicitly identify mismatched column names.
+  ([#3183](https://github.com/dotnet/SqlClient/pull/3183))
+- Optimized outgoing SSPI blob handling using `IBufferWriter<byte>`.
+  ([#2452](https://github.com/dotnet/SqlClient/pull/2452))
+- Replaced `byte[]` with `string` for SNI to improve efficiency.
+  ([#2790](https://github.com/dotnet/SqlClient/pull/2790))
+- Code cleanup to remove SQL 2000 support.
+  ([#2839](https://github.com/dotnet/SqlClient/pull/2839),
+   [#3206](https://github.com/dotnet/SqlClient/pull/3206),
+   [#3217](https://github.com/dotnet/SqlClient/pull/3217))
+- Connection pool design refactor for a modular connection pool design.
+  ([#3199](https://github.com/dotnet/SqlClient/pull/3199))
+- Added dependency on `System.Text.Json`
+  [8.0.5](https://www.nuget.org/packages/System.Text.Json/8.0.5) (.NET 8.0) and
+  [9.0.5](https://www.nuget.org/packages/System.Text.Json/9.0.5) (.NET Standard 2.0, .NET 9.0)
+  to avoid transitive vulnerabilities ([CVE-2024-43485](https://github.com/advisories/GHSA-8g4q-xg66-9fp4)).
+  ([#3403](https://github.com/dotnet/SqlClient/pull/3403))
+- Updated various dependencies [#3229](https://github.com/dotnet/SqlClient/pull/3229), primarily:
+  - System.Text.Encodings.Web to v8.0.0
+  - System.Text.Json to v8.0.5
+  - Azure.Identity to v1.13.2
+  - Microsoft.Identity.Model.Json.Web.Tokens to v7.7.1
+  - Microsoft.Identity.Model.Protocols.OpenIdConnect to v7.7.1
+- Code merge towards a unified SqlClient project, aligning .NET Framework and .NET Core implementations.
+  (Many PRs - see [6.1.0-preview1](6.1.0-preview1.md) and [6.1.0-preview2](6.1.0-preview2.md) for details.)
+- Test improvements include a new unit test project, updates to test
+  dependencies, removal of hardcoded credentials, and improved robustness.
+  (Many PRs - see [6.1.0-preview1](6.1.0-preview1.md) and [6.1.0-preview2](6.1.0-preview2.md) for details.)
+
 ## Contributors
 
 We thank the following public contributors. Their efforts toward this project
@@ -70,13 +285,26 @@ are very much appreciated.
 - [edwardneal](https://github.com/edwardneal)
 - [emmanuel-ferdman](https://github.com/emmanuel-ferdman)
 - [ErikEJ](https://github.com/ErikEJ)
+- [MichelZ](https://github.com/MichelZ)
 - [twsouthwick](https://github.com/twsouthwick)
 - [Wraith2](https://github.com/Wraith2)
 
 ### New Contributors
 
-- [frankbuckley](https://github.com/frankbuckley) made their first contribution
-  in [#3521](https://github.com/dotnet/SqlClient/pull/3521)
+- [BradBarnich](https://github.com/BradBarnich) made their first contribution in
+  [#3325](https://github.com/dotnet/SqlClient/pull/3325)
+- [deusanyjunior](https://github.com/deusanyjunior) made their first contribution in
+  [#3310](https://github.com/dotnet/SqlClient/pull/3310)
+- [emmanuel-ferdman](https://github.com/emmanuel-ferdman) made their first contribution in
+  [#3041](https://github.com/dotnet/SqlClient/pull/3041)
+- [frankbuckley](https://github.com/frankbuckley) made their first contribution in
+  [#3521](https://github.com/dotnet/SqlClient/pull/3521)
+- [JNjenga](https://github.com/JNjenga) made their first contribution in
+  [#3183](https://github.com/dotnet/SqlClient/pull/3183)
+- [MaceWindu](https://github.com/MaceWindu) made their first contribution in
+  [#3134](https://github.com/dotnet/SqlClient/pull/3134)
+- [Midhunnnk](https://github.com/Midhunnnk) made their first contribution in
+  [#3250](https://github.com/dotnet/SqlClient/pull/3250)
 
 ## Target Platform Support