Re: isearch multiple buffers

[Richard Stallman]

    What would be the criteria for still keeping support?

How much users want support for a platform is the question
I hope this will answer.

    One could be that 22.1 should be still functional on the platform.

We should not desupport a platform just because it has a bug.

    If one user has a machine in the basement that gets turned on once a
    year, would that qualify?

I don't think there should be any particular fixed threshold.  The
more users want it, the more work it's worth doing to support it.