I meant "errors", not "warning". Original node updated.

Usually, one has the my as part of the variable initialization, like my %foo = ();, not separately. Perl is closer to C++ and Java than C, in that regard. Also, you can just say my %foo; and it will work as expected.

As for why it changed ... I have no idea. 5.004_xx is somewhat different than 5.005_xx and above, in any number of ways. I wouldn't look to compare the two. (The way to think about them is that 5.004 is really 5.4, as compared to 5.6 and 5.8.)