[CentOS] Old and new package version numbers during RPM update

> Thanks Joseph. I am aware of this option, but it would be only a last resort, because checking the format of the config file is error-prone.
>
> I would prefer RPM to tell me the old and new version numbers, so my question still stands.

Well normal convention would be if you replace then the old one
gets appended with .rpmsave, if you are not replacing then the new
one gets appended with .rpmnew.

On the other hand, check this out:
https://www.redhat.com/promo/summit/2010/presentations/summit/opensource-for-it-leaders/thurs/pwaterma-2-rpm/RPM-ifying-System-Configurations.pdf

Seems you are in luck, you can infer what exists by virtue of the
order upgrades are installed.

Hth,
jlc