2.2.25 [RFC3501] Section 6.3.1, SELECT Command

  • Article

V0036:

The specification states that the server MUST send the following untagged data to the client before returning a tagged OK for the SELECT command response: FLAGS, EXISTS, RECENT, UNSEEN, PERMANENTFLAGS, UIDNEXT, and UIDVALIDITY. The specification also states that the client implementation SHOULD have default behavior for handling a SELECT response that is missing the required untagged data.

Microsoft Office Outlook 2007, Microsoft Outlook 2010, Microsoft Outlook 2013, Microsoft Outlook 2016, Microsoft Outlook 2019

Outlook requires the EXISTS untagged data and the UIDVALIDITY untagged data for proper operation. Outlook is unaffected if any of the following untagged data are missing: FLAGS, RECENT, UNSEEN, PERMANENTFLAGS, or UIDNEXT.

V0037:

The specification notes the following consequences for the client when the SELECT command response is missing certain untagged data:

  • UNSEEN ― If this data is missing, then the client cannot make any assumptions about the first unseen message in the mailbox, and needs to issue a SEARCH command if it wants to find it.

  • PERMANENTFLAGS ― If this data is missing, then the client should assume that all flags can be changed permanently.

  • UIDNEXT ― If this data is missing, then the client cannot make any assumptions about the next unique identifier value.

  • UIDVALIDITY ― If this data is missing, then the server does not support unique identifiers.

Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019

Outlook's behavior for each of these missing untagged data items is as follows:

  • UNSEEN ― Outlook ignores this data and, therefore, takes no special action if it is missing.

  • PERMANENTFLAGS ― Outlook always assumes that all flags can be changed permanently.

  • UIDNEXT ― Outlook ignores this data and, therefore, takes no special action if it is missing.

  • UIDVALIDITY ― Outlook does not function properly against a server that does not support unique identifiers.

V0038:

The specification states: "If the client is permitted to modify the mailbox, the server SHOULD prefix the text of the tagged OK response with the READ-WRITE response code."

Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019

Outlook ignores the READ-WRITE response code and, therefore, takes no special action if a folder is advertised as READ-WRITE.

V0039:

The specification states: "If the client is not permitted to modify the mailbox but is permitted read access, the mailbox is selected as read-only and the server MUST prefix the text of the tagged OK response to SELECT with the READ-ONLY response code."

Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019

Outlook ignores the READ-ONLY response code and, therefore, takes no special action if a folder is advertised as READ-ONLY.