RU7 for SP1 is out:
Some of the most important fixes are listed below (taken from above Exchange Team post):
First off, we fixed the SCR issue which have caused everyone some pain and which did not get completed in time to be included in the last update roll-up.KB 961281 Update Roll-up 5 for Exchange Server 2007 Service Pack 1 introduced an issue where you receive an error when attempting to enable SCR on a storage group if the environment has a parent domain -> child domain active directory structure. Tim has blogged about this over here. This is now fixed. Additionally, there are also 2 other SCR related issues which we have been addressed in this roll-up and have been asked for by many customers.KB 957834 Network shares are deleted and created intermittently by the replication service on an Exchange SCC cluster when SCR is enabled on the Exchange server
KB 958331 Restore-StorageGroupCopy command may fail in an Exchange Server 2007 SCR environment.
We have also fixed two issues which caused intermittent crashes in the IMAP4 service and resulted in event 4999 being logged in the event logs. The following KBs have more information on the scenarios which are fixed: KB 957504 and KB 960292.
MVP - Exchange Server