The differences are very minor, rules rephrasings and clarifications mostly. You should have no trouble playing any version of EF2 with any version of WF2.
Note: EuF2 is the ultimate arbitrator of current XFront rules. Columbia does not want frequent updates of EF2/WF2, but EuF2, due to it's inherent breadth and depth, is updated more frequently.
By the way, what has happened to the Eurofront website? It seems to be down since weeks ago.