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Highlights
Environment Configuration Support (experimental)
Users can now use Temporalio.Client.EnvConfig.ClientEnvConfig to load environment configuration from config files or environment variables. This is the same configuration approach that can be used across other SDKs and CLI. See https://docs.temporal.io/develop/environment-configuration for more details.
Nexus Support (experimental)
The Nexus .NET SDK has been released and this release adds Temporal support for implementing Nexus services with Temporal and calling Nexus services from Temporal workflows. See the Temporal SDK Developer Guide, Nexus SDK README, the Temporal SDK README section, and the initial Nexus .NET sample.
💥 MINOR BREAKING BEHAVIOR CHANGE - Serialization Context Change in Workflows
For advanced users of custom converters/codecs that were also leveraging the recent serialization context feature, there is a slight change in how they are handled in workflows. Previously, we eagerly created and used the converter/codec for all workflow use with the singular workflow context which meant we "stacked" contexts when they were also used for activities and children and such. Now we are properly not stacking the outer workflow context when making these other calls. So technically if there was a custom converter using advanced serialization contexts that relied on this context stacking, this can be a breaking change. See the PR at #525 for more details.
💥 MINOR BREAKING BEHAVIOR CHANGE - TLS cert override causes native certs to not be used
When a TLS server CA cert is explicitly set in TLS options to override system roots, the system roots will not be loaded. Prior to this version, system roots would still be loaded even if cert overrides were present.
Specific Changes
2025-09-18 - 45e61c8 - Activity reset (#521)
2025-09-18 - 95f840a - Fixed error message of BinaryProtoConverter.AssertProtoPayload not filling a placeholder (#520)
2025-09-22 - 2319df1 - Added retry policy to activity info (#511)
2025-09-22 - 8db923c - Env config (#509)
2025-09-22 - da7202a - Nexus support (#517)
2025-09-22 - e29940d - Added summary to local activity options (#524)
2025-09-25 - d4a0765 - Update version to 1.9.0 (#527)
2025-09-25 - f99bca3 - 💥 Fix how serialization context is applied in workflows [MINOR COMPAT BREAK] (#525)
2025-09-25 - fad7fb3 - Fix issue with search attribute keyword list type (#529)