Microsoft has released Update Rollup 2 for Exchange Server 2007 Service Pack 1
>> Update Rollup 2 for Exchange Server 2007 Service Pack 1 (KB948016)
Update Rollup 2 for Exchange Server 2007 Service Pack 1 (SP1) resolves issues that were found in Exchange Server 2007 SP1 since the software was released. This update rollup is highly recommended for all Exchange Server 2007 SP1 customers.
For a list of changes that are included in this update rollup, see KB948016.
This update rollup does not apply to Exchange Server 2007 Release To Manufacturing (RTM). For a list of update rollups applicable to Exchange Server 2007 RTM, refer to the section Update rollups for Exchange Server 2007 RTM in the Knowledge Base article KB937052.
This is a cumulative update rollup and replaces the following:
KB945684 Update Rollup 1 for Exchange Server 2007 Service Pack 1 (KB945684)
>> Update Rollup 2 for Exchange Server 2007 Service Pack 1 (KB948016)