I often see people wondering why Microsoft does not support Staged migration with Exchange 2010 or 2013. It’s hard to actually find an ‘official’ statement detailing on the exact reasons. But it seems that they are planning on bringing support for it, and here is the info direct from the source:
“We are looking into supporting Staged for 2010 and above… It’s on the roadmap to build some support around it… The problem is, 2010 and above don’t support setting targetaddress and that’s the bug that we couldn’t get fixed in time…”
By “source” I mean official Microsoft representative, speaking in front of a large audience at Ignite 🙂 No timeframes were mentioned, but I can take this as a confirmation. You can listen to this in the video below, around the 4th minute.
Another point worth mentioning is that it is not necessary to actually do the targetaddress part if you are using 2010/2013:
“I understand that people find Hybrid a little hard to set up and therefore want to use Staged, and so to support these scenarios, we are thinking about this (supporting Staged for 2010 and above). But in the interim, you can use New-MigrationBatch and do this -Skipsteps (i.e. use the parameter) and you can skip the targetaddress setting. Once you do that, it will work against 2010, but it will just do a one-shot sync. So if you wanna do a re-sync, you will have to recreate and redo it.”
While you can certainly do the batch with skipping the targetaddress step, remember that this step is actually recommended. Highly recommended, as it takes care of the mail flow. If you don’t do it, mail will not be forwarded from the on-prem mailbox to the cloud and they will be out of sync. As mentioned above, the only way to resync it will be to rerun the migration batch. And if you have converted the mailbox to mail-enabled user without setting the targetaddress, you will lose the new messages. Of course, you can set the targetaddress manually instead of relying on the migration process, albeit not supported.
Here’s the documentation on the New-MigrationBatch cmdlet that lists the parameter:
The SkipSteps parameter allows you to skip the step of setting the target email address on the source mailbox. This prevents mail from being forwarded from the original mailbox to the new mailbox that was migrated to the target destination. Use one of the following values with this parameter:
This parameter is only enforced for migration batches for a staged Exchange migration.
One other important piece of information disclosed on the session was the confirmation that the MaxMessageSize for EWS will be increased past the 48MB limit. The increased size for messages functionality was brought by several ‘waves’ – first we got the increased limit for onboarding via the MRS service (Hybrid), followed by the increase of send/receive size (which allowed cutover/staged/IMAP migrations to also take advantage of the new size), and now the EWS protocol (used by Outlook for Mac and many 3rd party migration tools). Why they missed it in the first place? Because it’s a server specific setting, configured via the web.config XML files, so it took some reordering of the code.
And another important piece of information: Cross-premises *Calendar* delegation is on the roadmap! (listen around the 22 min mark)
Here’s a link to the session in case the embed breaks or something:
Experts Unplugged: Exchange Online Migrations: http://channel9.msdn.com/Events/Ignite/2015/BRK3112