v1.11 seem to be the first separate CPAN release.
The code needs to depend on it for 5.6 for the
hash interface to the constants needs to depend on it for 5.6 for the
hash interface to the constants..

Ref: http://www.cpantesters.org/cpan/report/2e861e66-8363-11e3-8f27-e9288806f0e4