macos 26 considerations

Thank you Prof Murdoch, that?s the context I was looking for. When 
xquartz did not work for you in Tahoe, did you try homebrew or macports? 
?xorg-server? and ?xinit? packages? The pair is a documented alternative 
to xquartz, and if I believe what I read, those are supposed to work on 
tahoe.

Some follow-on discussions for the crowd:

 1.

    Does there already exist or can we make an FAQ or caution-page for
    upgrading to tahoe? I suspect I?m not the only one who has
    considered taking the upgrade, and since downgrading is not easy
    (likely ?not possible? for some), I think having a reference to this
    on |mac.r-project.org| would be a ?Really Good Thing (tm)?.

 2.

    I believe XQuartz is for displaying the plot canvas when not using
    RStudio or Positron. If we can?t have xquartz, what else are we
    losing? As an incomplete alternative, for many plots one could use
    |httpgd| (if/when they fix some bugs) or other ?immediate?
    file-based rendering, though I think this does not work for |rgl|
    (perhaps others).

 3.

    The webpage says /?R 4.6.0 CRAN arm64 builds use macOS 14?/, which
    further concerns me wrt compatibility and package availability. I
    know it?s a complicated topic, perhaps it?s too soon to say with
    authority that tahoe is going to be safe for R and for compiled
    binary packages.

    This is likely related to Xcode and the MacOS SDK; I believe Tahoe
    ?really wants? Xcode 26 and the 26 SDK, and I believe (no refs atm)
    that older versions can be problematic on Tahoe. I understand
    backward compatibility is always a concern, perhaps that is why the
    dev build is targeting macos 14, xcode 14.3, and 14.4 SDK. There are
    a lot of talented people working tirelessly (and often thanklessly)
    on this process, the more I learn the more I am thoroughly grateful
    for their knowledge and efforts.

    Is there yet a clear pathway for advancing to more up-to-date
    versions? Or is it still murky and peppering the devs with questions
    like this is just accelerating their ?early retirement??

 4.

    Are all of my xcode/sdk questions above ?moot? when using the
    RStudio or Positron IDEs? They are not (afaict) using x11 to render
    their plots, though I?m not sure how they show rgl-based plots.

Thanks all, I appreciate your time.
Bill

On 2026-02-22 10:40 a.m., Bill Evans via R-SIG-Mac wrote:

I?ve been holding off upgrading to MacOS 26 for many reasons, most
related to yet-unsubstantiated concerns about R. Because it?s a new ABI,
I suspect the process would be similar to a major/minor release in R:
update the compile chain then re-install all packages. Is there a strong
recommendation for or against this upgrade? Are there safe or at least
less-risky pathways for upgrading the OS? Is R-devel regularly tested
against 26? Are there known unresolved problems, such as ?package xyz
does not currently work??

FTR: I?m currently on macos 15.7.4 using R-4.5.2, and there is nothing
inherently broken. I don?t have a /need/ to upgrade to 26 atm but fear
at some point that some tool I use (be it Parallels or something else)
may eventually require 26 for some or all of the desired functionality.
I?m just planning ahead (and holding back two colleagues, also on
macos-15.7).

I upgraded in the fall, and found that XQuartz didn't work, and its 
maintainer had stopped working on it.? Since I was planning some work 
on rgl that needed XQuartz, I downgraded and I'm still on Sequoia 15.7.2.

You should be aware that downgrading isn't easy:? you need to create a 
bootable external disk, reformat your main drive and restore from a 
backup.? I did it and didn't lose anything, but it wasted a day or so, 
during which I wondered whether my backups were really as complete as 
I hoped they were.

Duncan Murdoch

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