The following comment only applies if you'll use savegames made with patch 1.4:
There was a problem in patch 1.4 with the regeneration of the inventories of
traders. Because of this problem after some time the game crashes. Patch 1.42
fixes this. Because of a technical issue, however, it's impossible to totally
upgrade savegames made with version 1.4. As a result, some magical items lying
on the ground, might lose their properties when applying patch 1.42.
This does not apply for items which are in the inventory of your party.