.NET Driver release notes for 2026¶

This article contains the release notes for the .NET Driver, including the following when applicable:

Snowflake uses semantic versioning for .NET Driver updates.

See .NET Driver for documentation.

Version 5.6.0 (May 20, 2026)¶

Added .NET 10 support. Changed LangVersion to C# 13.
Added client-side telemetry instrumentation using System.Diagnostics.Activity (OpenTelemetry-compatible). When CLIENT_TELEMETRY_ENABLED=true (the default), the driver automatically instruments all command executions and their async variants, and sends telemetry data to Snowflake’s /telemetry/send endpoint. Activities are enriched with session context (warehouse, role, database, session ID) and report success or error status with exception details.
Added the public StartActivity extension method on SnowflakeDbCommand for creating custom client-defined telemetry activities. Custom activities use a separate activity source (Client_custom_activity).
Added DbType.AnsiStringFixedLength to the set of types mapped to Snowflake TEXT, matching existing support for AnsiString, String, and StringFixedLength.
Extended login-request telemetry with libc detection (LIBC_FAMILY, LIBC_VERSION). On Linux, the driver now reports whether the runtime uses glibc and includes the library version.
Reduced the default maximum CRL download size from 200 MB to 20 MB, aligning with other Snowflake drivers.

Fixed handling of transient server issues that resulted in sending a truncated JSON response.
Fixed an issue where connections with sessions that no longer existed on the server were reused from the pool, which previously caused repeated failures until the connection expired on its own. These connections are now detected and removed from the pool.

The driver now includes SPCS_TOKEN in login requests when running inside a Snowpark Container Services (SPCS) container (detected via the SNOWFLAKE_RUNNING_INSIDE_SPCS environment variable).
Extended login-request telemetry with cloud platform and environment detection (AWS Lambda, EC2, Azure VM/Functions, GCE/Cloud Run, GitHub Actions). Detection runs once at startup in the background within a 200ms timeout. You can disable this feature by setting the SNOWFLAKE_DISABLE_PLATFORM_DETECTION environment variable.
Added the workloadIdentityImpersonationPath connection parameter for authenticator=WORKLOAD_IDENTITY, which allows workloads to authenticate as a different identity through transitive service account impersonation.
Added the HonorSessionTimezone connection parameter (default: false). When set to true, TIMESTAMP_LTZ values honor the session TIMEZONE parameter (set using ALTER SESSION SET TIMEZONE) instead of the local machine timezone. This will become the default behavior in a future major release.

Fixed an issue where idle sessions were not evicted from the connection pool when closing them fails.
Fixed an issue where sessions that receive HTTP 401 during query execution were returned to the connection pool.
Fixed GetResultsFromQueryIdAsync not aborting queries on the server when a CancellationToken is cancelled. Previously, only client-side polling stopped while queries continued running on Snowflake.
Fixed Azure GET (download) operations incorrectly reporting an UPLOADED result status instead of DOWNLOADED when the server returns presigned URLs for an encrypted stage.
Fixed query context cache not being updated when the server returns queryContext in a failed query response.
Improved CRL issuer validation: issuer names are now compared using DER encoding (avoiding string-form mismatches such as S= vs ST=), and the CRL’s Authority Key Identifier is verified against the issuing CA’s Subject Key Identifier when both extensions are present.

Extended login-request telemetry with Linux distribution details parsed from /etc/os-release.

Fixed IndexOutOfRangeException in Arrow result chunk processing by adding retry state cleanup, batch integrity validation, and defensive bounds checking in ExtractCell().
Fixed IndexOutOfRangeException when reading NUMBER/DECIMAL columns with scale greater than 9 in Arrow result format.

Added support for Red Hat Enterprise Linux (RHEL) 9.
Added support for the DECFLOAT data type (returned as string to preserve full precision).

Fixed IndexOutOfRangeException in Arrow result processing when empty batches are returned by the Snowflake backend.

Introduced a shared library for extended telemetry to identify and prepare the testing platform for native Rust extensions.