[erlang-questions] Arbitrary old versions feature

[Jon Schneider]

The (admittedly rather contrived) use case is where you have a large
number of mobile clients maintaining TCP (perhaps SSL) connections. They
pay a silly amount for mobile data so it would be best not to cut them
off. (Obviously the client software would re-connect anyway but it's the
principle here.)

There are two upgrade requirements in succession. Maybe it's a workaround
to deal with some nasty distributed denial of service that's just popped
up (and again something I've rather dreamt up).

The memory cost of keeping many copies of even large modules is
insignificant by modern standards.

I notice the old bits of the Module structure have changed since the
source (R15 ?) I looked at earlier so my thoughts on implementation are
somewhat invalid. Serves me right for not fetching latest code. Maybe
whoever changed that did so as a precursor to this feature.

Commit 166032bddf9a14f3ea6252724532039a1113612d specifically.

Jon