difference between old Lich king and new lich king

[DoFr]

wanted to download the expansion but said there's 2 options for Wrath of the Lich king

one of them had the word "old" next to it.

whats the difference between the two?

[Sankyo]

Wotlk OLD is the normal version of the Wotlk expansion character models. The other, include the Warlords of Draenor character models (characters, places, etc) which are better graphycs. It sometimes bugs for some people so i recommend you to download the old one, although you can change it later to the new if you want.