I haven't been able to find a version of Perl that actually warns in require v5.8.8;. All versions I tried either fail (because they don't understand v5.8.8;), or they just accept it.

I've seen people suggesting to use: 

use 5.006;      # First version to accept v-numbers.
require v5.8.8;

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In reply to Re: Portable way to require Perl 5.8.8 by JavaFan
in thread Portable way to require Perl 5.8.8 by rovf

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