We plan to setup exchange 2007. Our domain is a win2k domain and Exchange needs at least one 2003 DC, so we will have to exchange one win2k-DC for a 2003-DC. But what about the second DC, can it remain win2k or is the win2k-DC unable to replicate the AD objects/extensions/data/whatever that exchange 2007 creates? ...or do we need to upgrade the second DC as well?
The background to this question is of course: what if the new 2003 DC fails someday - will exchange still work afterwards?