2.2.17 [RFC3501] Section 6.3.4, DELETE Command

V0027:

The specification states: "It is permitted to delete a name that has inferior hierarchical names and does not have the \Noselect mailbox name attribute."

Microsoft Exchange Server 2007, Microsoft Exchange Server 2010, Microsoft Exchange Server 2013, Microsoft Exchange Server 2016, Microsoft Exchange Server 2019

Microsoft Exchange Server does not allow a mailbox to be deleted if it has inferior hierarchical names.