Was Re: [Exim] What do you want in a book?

> The book will be "3.16 with some 3.20 features", so a list of changes is
> already available by reading the 3.20 ChangeLogs onwards.

On a slightly unrelated subject, a thought occurred to me earlier.

Given the regular (and valid) changes to default values in minor releases,
would it be a good idea to have a "need_version" or "for_version" setting in
the config file so that if and when someone upgrades, they are reminded that
a config file may not work on a later version.

This could also be extended (possibly) with some small performance hit to
include the facility to carry forward "default" values between versions -
say where a user wants some bug fix but not a new feature - so that the exim
binaries maintained a set of tables keyed by release for these values ? Then
clear this out on each major release (like 4.xx etc.) ?

This may sound a bit of overkill, but exim is getting so flexible that it is
somewhat difficult to move from version to version without lots of
reading...

Peter