On October 2nd, 2023 CircleCI will sunset the medium and large macOS resource classes.
After 10/2, any jobs that run on a medium or large macOS resource will fail with an invalid resource class error.
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If you are using the medium resource class:
Update the resource class key in your configuration file from medium to macos.x86.medium.gen2.
Building with medium.gen2 will reduce your build time by up to 50%
If you are using the large resource class:
Update the resource class key your configuration from large to macos.m1.large.gen1
Our M1 large resource class offers 12 GB of memory and enables up to 2x faster builds and the ability to run end-to-end tests
Access to M1 is currently available on the Scale and Custom plans only. It will be available on the Performance plan in April.
Quote from the email I got: