We recently installed Exchange 2010 SP2.
Afterwards we noticed that MRSProxy service used for mailbox moves did not work anymore saying that the Mailbox Replication Proxy is disabled.
First thing we checked was the web.config on the CAS server and re-added the MRSProxyenabled value. Did not work.
We still got the error below.
Then we started searching for new cmdlets ( Or we should have read the release notes :) )
I noticed there were some new parameters when I ran the get-webservicesvirtualdirectory.
The parameter MRSProxyenabled was one of them.
So I ran "Set-WebServicesVirtualDirectory -MRSProxyEnabled $True" and voila, the MRSProxy was yet again enabled.
I confirmed the settings by running the "Get-WebServicesVirtualDirectory | fl ".
This showed the setting as enabled.
To be certain, I also restarted the Mailbox Replication Service on the CAS, afterwards mailboxes moved to Office 365 without issues.
Also documented in the release notes.