1) For 1. below , should I use Xcode15 or older version?
Xcode 15 or later is required on Sonoma.
2) Does the following procedure work? Is there anyone who has
successfully migrated Macport to Sonoma?
I haven't heard of any problems with the procedure that are specific to
Sonoma. Individual ports may fail to build, as is always the case with
new macOS versions. See <https://trac.macports.org/wiki/SonomaProblems>.
3) How long will this migration procedure take?
That depends on which ports you have installed and how fast your
hardware is. Since there are no binaries built yet, the majority of the
time will be spent compiling. There is information on ports.macports.org
about how long ports took to build on our buildbot, which should give
you a starting point; e.g.
<https://ports.macports.org/port/coreutils/builds/>.
4) I have upgraded to Sonoma OS. But why my present ports still work?
macOS is in general very backwards compatible, so existing binaries will
usually keep working on newer OS versions (though there are exceptions).
Unless you've hit one of the exceptions, the Migration procedure is only
needed to avoid problems when you upgrade your ports or install new
ones. As long as you never install or upgrade anything, you can keep
using your ports as is (though that's not recommended long term of course.)
- Josh
