Hi -
I applied the following hotfixes this weekend to Unity 4.2(1) running Windows 2003 SP1 and integrated with Exchange 2003 SP2. No problems encountered:
ms06-066, 067, 068, 071, and KB924334 (Exchange 2003 SP2 fix for OWA).
I did not apply 069, Macromedia Flash Player from Adobe. 070 was not applicable to our OS, that is for Windows 2000 SP4. Note: I always break the mirror set before applying maintenance, even if I've tested in test lab.
Hope this helps!
Ginger