all: end support for macOS 10.15 in Go 1.23

[dmitshur]

Go added support for macOS 14 that was publicly released this September. After internal discussion, we believe the summer of 2024 will be a good time to drop support for macOS 10.15. The last security update it received was in July 2022.

On behalf of @golang/release, I propose we announce the end of support in the Go 1.22 release notes, and disable the builder for Go 1.23.

CC @golang/darwin.

[rsc]

Usually we link to our macOS history in these issues. Is #23011 (comment) the most recent statement of our history? Is there a better policy link?

Regardless, since Apple stopped issuing updates in July 2022, and dropping in Go 1.23 would mean we stop issuing security patches (for Go 1.22) at the release of Go 1.24 in Feb 2025, that seems entirely reasonable. If anything we seem late.

[dmitshur]

We had been following that pattern of adding a new macOS version and dropping the oldest one every 2 Go major releases (i.e., once a year) for a long while. After Go 1.17, there was a longer period where we supported older macOS versions, but Go 1.21 caught up by dropping two at once (proposal #57125).

If this proposal is accepted, then:

• Go 1.22 (security patches until Feb 2025) is the last release with macOS 10.15 support
• Go 1.23 (scheduled for Aug 2024 release) drops macOS 10.15, requires macOS 11

And if we continue dropping oldest macOS once-every-two-major-Go-releases after that, the pattern would be:

• Go 1.24 (security patches until Feb 2026) last to support macOS 11
• Go 1.25 requires macOS 12
• Go 1.26 (security patches until Feb 2027) last to support macOS 12
• Go 1.27 requires macOS 13
• Go 1.28 (security patches until Feb 2028) last to support macOS 13
• Go 1.29 requires macOS 14
• ...

[lpar]

It would be good to have a page somewhere indicating minimum OS versions currently required for the Go toolchain, and minimum OS versions supported by the Go runtime. (Apologies if there is one, but I haven't been able to find it.)

[dmitshur]

@lpar Minimum OS version information is there but can be made easier to find—see #41212 for that.

[randall77]

https://github.com/golang/go/wiki/MinimumRequirements lists the minimum OS versions we require.

[lpar]

Thanks. Do the minimum version requirements apply to the runtime for built binaries?

[randall77]

@lpar I'm not sure what you are asking. They apply to everything in the built binary, runtime included.

[lpar]

Thanks, that was what I was asking, whether ending support for macOS 10.15 meant that binaries compiled by the Go toolchain would no longer be supported on 10.15.

(Binaries built with Go 1.21.x still seem to work on some unsupported macOS versions, but of course that doesn't mean it's supported that they do.)

[rsc]

Based on the discussion above, this proposal seems like a likely accept.
— rsc for the proposal review group

Following our usual pattern, more or less:

Apple stopped issuing security updates for macOS 10.15 in July 2022.
Go 1.22 (security patches until Feb 2025) is the last release with macOS 10.15 support
Go 1.23 (scheduled for Aug 2024 release) drops macOS 10.15, requires macOS 11