What does "Only for up-to-date Windows" mean?

Sorry for being dumb, but what does this mean on the MSI versions?

I’ve always used the exe versions and don’t upgrade UrBackup every single release, so can’t work out if I should be using the MSI version or not.

It need a windows component which was provided as a part of a microsoft update.
If you have the last windows update you’ll have this component installed
Search the forums you ll find more details about it.