Were it pure perl, it'd work. Unfortunately for modules with XS components you're probably not going to have any luck unless you stay within the same major revision (and then I don't know offhand if it's a written guarantee to maintain binary compatibility; I'm sure someone here may be able to quote chapter and verse one way or the other). At best you're likely to have something that just won't load like you're seeing; at worst you might get something which will load but then will randomly SEGV because the "shape" of some perl data structure has changed underneath it and it goes chasing what it thinks should be the foo pointer but is really the lower half of a long double now.