What does yum do when an updated package requires a new configuration file?

[Tim Largy]

Hi,

What does yum do when an updated package calls for a new configuration
file? A concrete (though made up) example: a new version of samba is
installed, and the syntax of /etc/samba/smb.conf has changed
sufficiently that the existing smb.conf is unreasonable or no longer
valid. (Of course in real life this hasn't happened with samba for a
while.) I presume that yum would notify me (how?), as well as save my
old smb.conf to a new name so that I could merge it with the new
version. The yum man page doesn't address this however.

Tim