CommuniGate Pro stores received messages in Account Mailboxes. The server supports several Mailbox formats, and the Mailbox type is defined by the Mailbox file (or directory) name extension.
For single-Mailbox Accounts, the Mailbox type is specified when the Account is created.
Each multi-Mailbox Account has a setting that specifies the default type for all new Mailboxes created in this Account. A user can explicitly specify the Mailbox type creating a Mailbox in a multi-Mailbox Account: if the Mailbox name is specified as name.extension, then the Mailbox name of the extension type is created.