Most particularly, see the first paragraph in the sub-section on 'Version Strings' in the section Scalar value constructors of perldata:
Note: Version Strings (v-strings) have been deprecated. They will be removed in some future release after Perl 5.8.1. The marginal benefits of v-strings were greatly outweighed by the potential for Surprise and Confusion.

In reply to Re^2: What's the difference between $heap->{127.2}{127.1.0.2} and $heap->{'127.2'}{'127.1.0.2'} ? by AnomalousMonk
in thread What's the difference between $heap->{127.2}{127.1.0.2} and $heap->{'127.2'}{'127.1.0.2'} ? by sunshine_august

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