Hi, I have migrated to Mageia, and found some of the settings were changed,
I found KDE4 settings changed mostly. so I renamed ~/.kde4 to kde4-old, and then installed mageia-1
the kernel is a different version, and any (custom) settings for modules may be errased (/etc/modprobe.d) and the module blacklist.
you might read the errata
, it describes a few things you may need to know.
Personally, I found the change over quite straight forward, but eventually, I have installed a clean (non upgrade/migrate) Mageia 1 install.