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

[Joseph L. Casale]

> I need to know this, because for a certain package, if updating from version 1.x to 2.x, I need to run a program to convert the config file of the package from version 1.x format to version 2.x format.

Your script within the rpm should have the logic. Clearly if
you know how to update it, you know how to identify if it
needs updating.

jlc