Do 4th edition rules change the game?

[Matt W]

Mike raised the point that the 4th edition had to be "backward compatible" with already issed products. That does not mean that new editions of existing products may not have to be issued (indeed, given some of the editing errata some of it may be necessary!). On the other hand, I would like to be able to avoid buying the units, maps, counters, standard rules, charts and game box all over again to get the 2 pages of edits to the SSRs necessary to update the package I already have.

I would be willing to pay something to get the update, but my days of buying something just because it says Panzer Grenadier on it are beginning to fade.