any 5.8.x version should be binary-compatible.
I should qualify that: Any 5.8.x version that shares the same architecture should be binary-compatible. That is, FC's 5.8.4 and the default 5.8.1 should be, because they're both built for darwin-thread-multi-2level.
If a Perl 5.8.4 is built without thread support - i.e. for arch darwin-2level - it wouldn't be compatible with the default 5.8.1.
sherm--
