there is an upgrade option during the install process. it comes after selecting your language, accepting the licensing agreement, & after it searches the drive for installed OS's. you can then choose a clean install or upgrade if a previous version of MDK was found. if you choose clean install, you will get further options for auto-allocate disk space, wipe the drive & install, or expert mode which lets you custom partition the drive.
a note about the upgrade option..........
that is sometimes a point of contention with MDK users. you might read many posts about how it isn't a good idea & doesn't always work. you will also see many posts as to how nicely it works with no problems. i personally have used the upgrade option since version 9.1 & have had no problems with it. your mileage may vary.
regardless, you're still going to need the install CD's for 10.0 official. if what your asking is, is there an auto upgrade option like Gentoo "emerge", or to that affect, the answer is basically "no", unless you want to run cooker, have the cooker sources installed, have an internet connection, & do urpmi --auto --auto-select. that will upgrade the distro to the current cooker version. but, since cooker is a testing ground for the new MDK versions, doing an upgrade that way can have results that you may not appreciate. (anything from a few unstable apps, to a completely useless install) use cooker at your own risk.