I've noticed when I select a folder of messages (Thunderbird) and mark them all as read (or unread) it produces the following IMAP transcript:

Source Destination Info c.c.c.c s.s.s.s Request: DONE s.s.s.s c.c.c.c Response: 20 OK Idle completed. c.c.c.c s.s.s.s Request: 21 uid store 1:20 -Flags (\Seen) s.s.s.s c.c.c.c Response: * 1 FETCH (UID 1 FLAGS (\Recent NonJunk)) c.c.c.c s.s.s.s Request: 22 UID fetch 2 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 2 FETCH (UID 2 RFC822.SIZE 1339 BODY[] {1339} c.c.c.c s.s.s.s Request: 23 UID fetch 3 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 3 FETCH (UID 3 RFC822.SIZE 1342 BODY[] {1342} c.c.c.c s.s.s.s Request: 24 UID fetch 5 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 5 FETCH (UID 5 RFC822.SIZE 1344 BODY[] {1344} c.c.c.c s.s.s.s Request: 25 UID fetch 6 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 6 FETCH (UID 6 RFC822.SIZE 1350 BODY[] {1350} c.c.c.c s.s.s.s Request: 26 UID fetch 7 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 7 FETCH (UID 7 RFC822.SIZE 1344 BODY[] {1344} c.c.c.c s.s.s.s Request: 27 UID fetch 8 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 8 FETCH (UID 8 RFC822.SIZE 1325 BODY[] {1325} c.c.c.c s.s.s.s Request: 28 UID fetch 9 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 9 FETCH (UID 9 RFC822.SIZE 1323 BODY[] {1323} c.c.c.c s.s.s.s Request: 29 UID fetch 10 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 10 FETCH (UID 10 RFC822.SIZE 1338 BODY[] {1338} c.c.c.c s.s.s.s Request: 30 UID fetch 11 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 11 FETCH (UID 11 RFC822.SIZE 1333 BODY[] {1333} c.c.c.c s.s.s.s Request: 31 UID fetch 12 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 12 FETCH (UID 12 RFC822.SIZE 1344 BODY[] {1344} c.c.c.c s.s.s.s Request: 32 UID fetch 13 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 13 FETCH (UID 13 RFC822.SIZE 1335 BODY[] {1335} c.c.c.c s.s.s.s Request: 33 UID fetch 15 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 15 FETCH (UID 15 RFC822.SIZE 1323 BODY[] {1323} c.c.c.c s.s.s.s Request: 34 UID fetch 16 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 16 FETCH (UID 16 RFC822.SIZE 1325 BODY[] {1325} c.c.c.c s.s.s.s Request: 35 UID fetch 17 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 17 FETCH (UID 17 RFC822.SIZE 1333 BODY[] {1333} c.c.c.c s.s.s.s Request: 36 UID fetch 18 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 18 FETCH (UID 18 RFC822.SIZE 1327 BODY[] {1327} c.c.c.c s.s.s.s Request: 37 UID fetch 19 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 19 FETCH (UID 19 RFC822.SIZE 1343 BODY[] {1343} c.c.c.c s.s.s.s Request: 38 UID fetch 20 (UID RFC822.SIZE BODY.PEEK[]) s.s.s.s c.c.c.c Response: * 20 FETCH (UID 20 RFC822.SIZE 1337 BODY[] {1337} c.c.c.c s.s.s.s Request: 39 IDLE s.s.s.s c.c.c.c Response: + idling

NOTE: c.c.c.c = client (thunderbird) s.s.s.s = server (dovecot 1.1.2)

Is this reasonable? I thought it would be possible to just send a list of message UIDs and say mark these as /seen /unseen etc.

Of course this could (is probably) just Thunderbird being braindead but confirmation would be appreciated.

Thanks, Daniel