This does appear to be the plan: https://github.com/golang/go/issues/56539#issuecomment-1332585915 https://github.com/golang/go/issues/56539#issuecomment-13325.

This does appear to be the plan: https://github.com/golang/go/issues/56539#issuecomment-1332585915 https://github.com/golang/go/issues/56539#issuecomment-13325... It would be up to the implementation whether the default result from MultipathTCP is on or off, and then programs could override that with SetMultipathTCP. In Go 1.21, we would default it off everywhere, and then in Go 1.22 or later, we would turn it on by default for systems that support it. Support might mean that it's an operating system that we have code for, or it might mean a more precise result, that we've sniffed the current kernel to see if it's available. That detail is up to the implementation and can change over time.