Moving from Public Folder Free/Busy to CAS in Exchange 2007

It is indeed automatic. As you install Exchagne 2007, setup asks you if you have Outlook 2003 or earlier clients. If so, it makes sure to store busy in Public Folders AND make it available via the "Availability Service," which Outlook 2007 and later clients user to access F/B data directly from the mailbox.  This blog has details on how it works: http://msexchangeteam.com/archive/2006/10/23/429296.aspx

It is correct that Outlook 2003 and earlier, used pulic folder for free/busy information.
If all clients are Outlook 2007, they will automatically use the new web services (Availability service) way instead of public folder when they publish free/busy information.
But if you opted to support earlier clients during the Exchange 2007 install, it installed automatically a public folder database. And I guess you set up replication between them?

So yes, you can just shut down your old Ex2003 box and clients will still find the correct free/busy information. If you are not sure, just shut it down and watch what happens.
After you confirmed it works, you can go further on and dismount the public folder database on the Exchange 2007 server. If all still works, then you can safely delete the public folder database.

Also, read this information here (How to Remove the Last Legacy Exchange Server from an Organization):
http://technet.microsoft.com/nb-no/library/bb288905(en-us).aspx

Aha, so when I chose the option that said i still had legacy clients, this meant that FB information was stored in the PF (which are replicated) *and* the mailbox  (which can be accessed via CAS)?

Yes, that's correct.

Ok, thanks...

Just to get this right in my head, can I ask one further question:

Let's say I am running Exchange 2007/2003 mailbox servers. When I installed the Exchange servers, I chose the option that said I had both OL 2007 *and* 2003 clients.

So, according to what I understand, this means that FB information for Exchange 2007/OL 2007 users is stored in both the user's mailbox and the FB Public Folders).

Let's say I have User1 (who uses Outlook 2007) on an Exchange 2003 server. At the moment, all his FB information is stored in the FB Public Folder folder that is special for each Adminstrative Group in Exchange, but replicated everywhere.

I then move his mailbox to Exchange 2007. You are saying that now his FB is held on both his mailbox *and* the PF on his Exchange 2007 mailbox server? Is there no informaion held on the FB public folder that previously hosted his FB info?

Also, would be I be correct in saying that now other OL 2007 clients (provided the mailbox is located on 2007) use the FB in his mailbox, via the Availability service, to access his FB info? Only OL 2003 and OL 2007 clients not on Exchange 2007 will use the Public Folder (although I'm not sure which PF)?

Yes, you are right all the way.

When you move a mailbox from 2003 to 2007, Exchange will change its preferred method of showing FB into the Availability service. And it will be published in the service as well as the PF DB on the Exchange 2007 server.

One thing, for that all Outlook 2007 clients will do this automatically when you move a mailbox from a Exchange 2003 server into Ex2007 AND the client is Outlook 2007, is to use the Autodiscover service as well. If you have manually configured Outlook 2007 clients on Ex2007, it will not work. Think of it as Autodiscover beeing the mother of all services, and that most other services relies on the Autodiscover service.

Thanks xcommiii

But I'm not sure I understand your last paragraph?

"One thing, for that all Outlook 2007 clients will do this automatically when you move a mailbox from a Exchange 2003 server into Ex2007 AND the client is Outlook 2007, is to use the Autodiscover service as well. If you have manually configured Outlook 2007 clients on Ex2007, it will not work. Think of it as Autodiscover beeing the mother of all services, and that most other services relies on the Autodiscover service. "

The last paragraph means the following: If you are using Outlook 2007 against Exchange 2003, Outlook will look at public folders for Free/Busy info (since Exchange 2003 does not have the availability service). If you migrate that mailbox to Exchange 2007, Outlook 2007 will automatically switch to using the availability service for F/B information (now, the F/B data is in both the public folder AND the availability service). It knows to do this because Exchange 2007 has another service call "autodiscover" that adverstises information useful to Outlook, such as which how to access the availability service. You don't need to take any steps to make this happen, it does so automatically.

Thanks guys. think I understand it now! :)

Just one last question:

"If you are using Outlook 2007 against Exchange 2003, Outlook will look at public folders for Free/Busy info (since Exchange 2003 does not have the availability service). If you migrate that mailbox to Exchange 2007, Outlook 2007 will automatically switch to using the availability service for F/B information "

When you say that Outlook will use the Public Folders/Availability service, is this to check the FB information of other users (e.g. when making an appointment) or to check the FB information of the actual user so that his own Calendar can be populated?

So, to re-phrase:

If User1 is on Outlook 2007/Exchange 2007, will Outlook check the availbility service to check User1's own FB information? Or will it only check the availability if User1 wants to schedule a meeting with User2, and so in this case User1's Outlook will check the availbility service for User2's FB information?

Thanks so much :)

Any idea guys?

Thanks...

"Anyway, why do you wonder so much about this? In a proper migration/coexistence scenario with both Outlook 2003/2007 clients, all this is handled transparently by the Exchange 2007 servers. "

- I just like to know as much as I can about Exchange :)