RFC 5162 [3.1] states that a QRESYNC should return all changes in a
SELECT/EXAMINE since the given modseq. In the following case, it
looks like there is an off-by-1 error somewhere:

C: A64 SELECT "TestMailboxTest" (QRESYNC (1224531494 6 1,3:5)) [MMS: MODSEQ given is 6] S: * OK [CLOSED] S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) S: * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)]
Flags permitted. S: * 4 EXISTS S: * 0 RECENT S: * OK [UNSEEN 1] First unseen. S: * OK [UIDVALIDITY 1224531494] UIDs valid S: * OK [UIDNEXT 6] Predicted next UID S: * OK [HIGHESTMODSEQ 6] [MMS: HIGHESTMODSEQ is 6 - the same as our cache, so there should be
no need for an update] S: * 2 FETCH (MODSEQ (6) UID 3 FLAGS (\Deleted)) [MMS: ...but we get this FETCH that contains the MODSEQ ID of 6, which
we have already told the server we are aware of] S: A64 OK [READ-WRITE] Select completed.

In other words, I don't think that "2 FETCH ..." should be in the
server response - it is duplicative information as to what is already
cached on the client.

michael