Microsoft released the service definition documents for the dedicated versions of Office 365 on October 4, 2011. The dedicated subscription plans add to the existing range of “P” (professional and small business) and “E” (enterprise) plans that are available now.

Dedicated subscriptions are typically taken up by large companies that support more than 30,000 mailboxes (up from the 5,000 requirement in BPOS). Support, or rather the quality of support, is the big difference between running a dedicated instance of any service and taking out a subscription to a general-purpose service. A dedicated instance typically comes with the kind of hands-on customized attention from Microsoft that enterprise customers have become accustomed to and expect. The revenue associated with a dedicated instance is sufficient to warrant attention from local Microsoft management too, so any problem that occurs during a migration or during operations is usually handled with a level of local knowledge and customized attention that you simply don’t get from the phone support available to customers who purchase Microsoft’s “E” plans. And customers who buy the “P” plans (like myself) don’t get support at all, unless you consider the opportunity to consult sources such as web sites, blogs, and Twitter when things go wrong to be within the definition of “support”!

Releasing these documents allows companies who might consider a dedicated instance to begin the work to analyze their options. A lot of up-front preparatory work is usually necessary to figure out how best to perform a migration. In addition, there’s the small matter of negotiating the conditions for a dedicated subscription, including pricing, with the local Microsoft sales team, a process that invariably takes time before all the t’s are crossed and i’s dotted and the deal is signed.

Large-scale migrations don’t happen overnight and flawless hybrid co-existence is a sine que non before it can start. The release of Exchange 2010 SP2 and its hybrid co-existence wizard will make the task of setting up data sharing and mailbox moves between on-premises and cloud servers much easier. Exchange 2010 SP2 hasn’t been released yet, so that’s another item on the checklist that large companies have to wait for, plus of course the time that they’ll need to test out SP2, introduce it into production, and the configure everything to work with Office 365 – and set up Active Directory Federation Services to support single sign-on between the two environments.

All of these factors probably mean that the deployment of dedicated instances of Office 365 won’t start until sometime in 2012. BPOS customers who are champing at the bit to move to a more modern platform (and one that is hopefully more reliable) have been told to wait until Microsoft is ready to move them as there’s a lot of work to be done to smooth the passage of mailboxes, mail routing paths, and other settings from BPOS to Office 365.

In the meantime, the documents released by Microsoft indicate that they’ll have two kiosk (browser-based) and four enterprise plans for dedicated subscriptions. Details of the different variants of SharePoint Online and Lync Online can be found in the service description documents.

Table 1. Office 365 Suite Plans

The Exchange Online variant of Office 365 comes in three flavors. The kiosk (K) plan is browser-based and replaces the old deskless worker approach taken in BPOS. Table 2 provides an overview of what you get in each plan.

Table 2. Messaging Plan Feature Overview

¹ Plan names for Exchange Online have changed under Microsoft Office 365. Kiosk D Plan was formerly Deskless Worker, Plan 1D was formerly Standard, and Plan 2D is a new plan.

² Inbox rules, instant messaging (IM) integration, short message service (SMS) integration, and access to other mailboxes are disabled.

³ Intranet only.

⁴ Hosted voicemail is a Tech Preview feature for early adopter customers. During the Tech Preview, users with Exchange Online Plan 1D subscriptions can also access hosted voicemail.

Of course, these documents represent Microsoft’s thinking as of now and are subject to change. However, I think that they are an aid to planning. It also allows companies to compare and contrast the alternatives that are available from other hosting companies who are able to provide dedicated instances of Exchange 2010, SharePoint 2010, and Lync 2010 customized to your requirements. Let the fun begin!

Candidate for worthless tweet of the week (as repeated ad nausem by people who have very little of their own opinions to share): “What do Disneyland and @Office365 have in common? They are both open 365 days a year.” 

– Tony

PS. Some readers have commented on my WindowsITPro.com blog “Writing books about Microsoft technology just got a little bit harder” and asked if I plan to write any more books on Exchange. For now the answer remains maybe, just maybe…