Pure perl modules are not, unless they use syntactic features that first appear in the newer versions.
Modules with C extensions have to be recompiled with libperl they run against, as much as CPython extensions link to a particular libpython, and guess Ruby is the same. But they, with very few exceptions, will recompile and run fine. XS is cryptic but its backwards compatibility story is good.
Modules with C extensions have to be recompiled with libperl they run against, as much as CPython extensions link to a particular libpython, and guess Ruby is the same. But they, with very few exceptions, will recompile and run fine. XS is cryptic but its backwards compatibility story is good.