HMC hosters, new Rollups are now approved for your 4 and 4.5 environments
The following rollups are now tested and approved for use in HMC 4 and 4.5 environments respectively. This will enable HMC hosters to run Exchange 2007 SP2!
HMC 4.0 - RU3
https://support.microsoft.com/kb/979702/en-us
HMC 4.5 - RU6