Sorry for not posting this sooner - I just found out about it today. As I noted previously, we recently fixed the MAPI download to work on Vista and Windows Server 2008. This broke some ISVs who weren't expecting Exchange's MAPI to use the MAPI stub library. So, to give ISVs time to validate their applications with the new download, we've reposted the old one. Now there are two download pages:
Note that the older installer is only being offered until August 15th.
Update: The pre-Vista package has been taken down. See Pre Vista Fix MAPI Download No Longer Available.
This is a follow up to Pre Vista Fix MAPI Download Still Available . As promised, we kept the old pre-Vista