Intel has put the Celeron brand on all sorts of processors. It's not a very useful indicator of age or in support status.
Regardless, other than when they added Android app support that needs virtualization, I'd be surprised if anything added to Chrome OS since launch requires processor features that weren't present on the first x86/amd64 processors Chrome OS supported.
Chrome device support expiration is only based on device launch date; if someone else launched a device with the same basic hardware three years after yours, it gets three more years of support. If Google is in the middle of replacing the printer support, too bad, your final release can't use the old way or the new way; maybe printing isn't for you, etc.
This is something I've never understood. I would expect Chrome OS to be more like Linux or Windows, with a support cycle dictated by the software (including drivers) not the hardware.
Regardless, other than when they added Android app support that needs virtualization, I'd be surprised if anything added to Chrome OS since launch requires processor features that weren't present on the first x86/amd64 processors Chrome OS supported.
Chrome device support expiration is only based on device launch date; if someone else launched a device with the same basic hardware three years after yours, it gets three more years of support. If Google is in the middle of replacing the printer support, too bad, your final release can't use the old way or the new way; maybe printing isn't for you, etc.