How about making it a build-time config setting? Overridable by a use warnings parameter.
That way, people could specify that they don't want to see "just useful" warnings that didn't exist prior to some version. It wouldn't help those of us who use binary distributions, but we deserve what we get:)
It wouldn't be too onerous to add the version => 'x.x.x' to existing scripts that suddenly start bellyaching. I would imagine that most shops run a new distribution in a test environment for a while before upgrading production servers anyway?
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"Efficiency is intelligent laziness." -David Dunham
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