About a month ago, Microsoft released the Microsoft Solution for Hosted Messaging and Collaboration (HMC) 3.5 Feature Pack.  This feature pack made some changes to the Hosted Exchange (HE) component of the solution.  The core changes brought by the feature pack are focused on how the Exchange Resource Manager and Plans systems behave.

Pre Feature Pack Behavior

• Plans System controls mailbox features (POP, IMAP, OWA, & Outlook Client) and the mailbox size for a user.
• Each mail enabled organization must have a mailbox quota assigned to it.
• Each mail enabled user would consume a given amount of space of an organization’s quota based on the plan defined during mail enabling (or user creation).
• The only way to change a users mailbox size is to change the plan of the user.  This results in a large number of plans to facility the various plans (aka feature set) and mailbox sizes.

Feature Pack Behavior

• Organizations can be mail enabled, but not have a quota assigned.   The “trigger” for mail enabling an organization within the “CreateBusinessOrganization” procedure in the “Hosted Exchange” namespace is now based on the “SMTPDomain” element being provided as part of the XML request submitted to MPS.  Previously, the “trigger” for mail enabling and organization was the “mail” element.  (the mail element in the XML request holds information on quota size for an organization and (as an option) a collection (or single) targeted mailstores.)
  • As an example, the Hosted Exchange/CreateBusinessOrganization needs the following in order create a new organization that is mail enabled without a specific quota:
    <container> – LDAP Path to the Reseller OU
    <name >– the CN name that will be used for the new organization/customer
    <SMTPDomain> – This is the primary mail domain for the new organization
    <preferredDomainController> – Fully Qualified Domain Name (FQDN) for an Active Directory domain controller.
    <availablePlans> – A list (<planName>) of plans associated with this new organization.
    
• When mail enabling a user, if now specific mail store is targeted as part of the request AND there aren’t any mail stores assigned to an organization (e.g. when you assign a quota for an organization), then the Resource Manager will find any available space that is marked as Shared.
• As an example, as a new user is create using Hosted Exchange/CreateBusinessUser, the following properties are required to create a new user, mailbox, and leverage the new Feature Pack feature:
  • <preferredDomainController> – Fully Qualified Domain Name (FQDN) for an Active Directory domain controller.
    <container> - LDAP path to the customer OU
    <userPrincipalName> - This will be the new Logon used by the user to access their mail
    <displayName> - Display name of the new user
    <newPassword> - Password for the user.  This must be meet the password restrictions defined for the Active Directory domain.
    <planName> for the new organization
    <mailStore autoAllocate=”1”> - This specifies that no mailstores or quotas will be assigned to the organization and the RM should instead provide space dynamically per user.
    
• Additional explicit properties can be applied to a user during the CreateBusinessUser or CreateMailbox calls.
  • <mail>/<prohibitSendAndReceiveQuota> — The size in kilobytes required to set this; the default is 500 percent of size. The store default is used if the size is set to 0.
     <mail>/<outgoingSizeLimit> — The maximum size in kilobytes of outgoing messages; the default is unlimited (-1).
     <mail>/<incomingSizeLimit> — The maximum size in kilobytes of incoming messages; the default is unlimited (-1).
     <mail>/<recipientLimit> — The number of mail recipients for outgoing messages; default is unlimited (-1).
    
• After you create the user, in order to make a change to the users mailbox directly and outside of making a change to that users plan,  you’ll use the Hosted Exchange/ModifyUserMailboxQuota named procedure.

The deployment of the HMC 3.5 Feature Pack is a bit "weird" as it requires the uninstallation of components via the MPS Deployment Tools, copying files from the FP zip file over the existing MSI files in the "C:\MSIShares" folder, and then rerunning the deployment tool to install the updated components. Like I said, it's a bit weird, but straight forward.

Installation of the Feature Pack requires that a well deployed HMC 3.5 is already done.  Getting access to the FP is much the same as getting the HMC 3.5 solution, accept that the download is in an ISO file versus a ZIP file which the solution comes it.  So you'll need a tool (Nero or MagicISO) to extract the files.