quoted

If booted against an old kernel, it will
behave as though there is no modversions information.

Huh? This I don't get. If you have the new libkmod and boot
an old kernel, that should just not break becauase well, long
symbols were not ever supported properly anyway, so no regression.

Specifically, if you set NO_BASIC_MODVERSIONS, build a module, and
then load said module with a kernel *before* EXTENDED_MODVERSIONS
existed, it will see no modversion info on the module to check. This
will be true regardless of symbol length.

I'm not quite sure I understood your last comment here though,
can you clarify what you meant?

Anyway, so now that this is all cleared up, the next question I have
is, let's compare a NO_BASIC_MODVERSIONS world now, given that the
userspace requirements aren't large at all, what actual benefits does
using this new extended mod versions have? Why wouldn't a distro end
up preferring this for say a future release for all modules?

I think a distro will end up preferring using this for all modules,
but was intending to put both in for a transitional period until the
new format was more accepted.

  Luis