The other replies give the answers: the ABI has always been an implementation detail, and Go binaries are static built from source, so this change won't matter.

The other replies give the answers: the ABI has always been an implementation detail, and Go binaries are static built from source, so this change won't matter. But just to add to that: I've been using Go for 4-5 years, and have never needed to know or care about its calling convention. It doesn't even affect people that write functions for Go in assembly ... because as the proposal says, "This will remain backwards compatible with existing assembly code that assumes Go’s current stack-based calling convention through Go’s multiple ABI mechanism." So the Go developers have put a fair bit of thought and effort into making this just work, even bending over backwards to make assembly libraries keep working.