New-RemoteMailbox -Shared

I perform a lot of migrations to Exchange Online and do most of my work in PowerShell. As such, being able to work with all types of remote mailboxes for Exchange Online migrations is a boon to me as it is less time I have to spend in the GUI. Recently Microsoft added the ‘-Shared’ option to the New-RemoteMailbox cmdlet for Exchange 2013 CU21 and Exchange 2016 CU10. This now allows PowerShell to create a new remove mailbox in the cloud that is not a room equipment or user mailbox. While Shared mailboxes are not usually a significant number when considering all mailboxes in a migration, they are more visible as Shared mailboxes by their nature have more than user or viewer.
There are some caveats to the availability of the parameter for the New-RemoteMailbox cmdlet. From Microsoft’s documentation:

This switch is a great addition to the ones that Microsoft already includes with the New-RemoteMailbox cmdlet as see below:

Interesting Note
My Exchange 2013 Server which was upgraded to CU21 was able to utilize the ‘-Shared’ parameter for New-RemoteMailbox, but the helpfile was not updated to reflect the change. I also ran ‘Update-ExchangeHelp’ to ensure I had the latest help files with no luck. An Exchange 2016 Server I upgraded to CU10 was also missing the “-Shared” parameter from the help of New-RemoteMailbox.
Related Cmdlets
In addition to New-RemoteMailbox, don’t forget that Enable-RemoteMailbox and Set-RemoteMailbox are also updated with the new parameter for Exchange 2013 CU21 and Exchange 2016 CU10. In both my installation of CU21 (2013) and CU10 (2016), I saw the switch for Enable-RemoteMailbox, but not Set-RemoteMailbox. Set-RemoteMailbox instead uses -Type to specify the mailbox type: “-Type Shared”
Size Limits for Shared Mailboxes
While we are on the topic of Shared Mailboxes, some of you may have read about the sizing of Shared Mailboxes and how they were provisioned in Office 365 at the EHLO Blog. For some this may have been a shock when they realized that Shared Mailboxes, without a license, are limited to 50 GB. This limit was published a while ago HERE. While some may have been provisioned as 100 GB mailboxes, this was apparently done by accident. Make sure you are aware of the changes in case they affect your Shared mailboxes.