The Go SDK shifted toward serverless and observability patterns while tightening compatibility constraints. The minimum Go version jumped to 1.24.0 in v1.42.0, and cross-namespace workflow operations were deprecated as the server disabled them by default. Worker heartbeating graduated as a core feature in v1.41.0, spawning a background nexus worker to stream metrics to the server—requiring server 1.29.1+ and dynamic config flags to fully activate. The SDK also introduced a Lambda worker module for running tasks in AWS Lambda on server invocation, and deprecated v1/v2 worker option versioning in favor of a simpler model. Bug fixes addressed replay crashes when codecs fail during session cancellation, heartbeat context propagation on shutdown, and test environment timeout enforcement.