Couple of questions

[Ian G Batten]

On 21 Jul 08, at 2135, Steve Webb wrote:
> I've got pop users
> that can't access IMAP (using phones for checking email when on travel
> with "leave messages on server" then suck down the emails when they  
> arrive
> back at a desktop).

Have you confirmed that they can't use IMAP, or is that just what they  
say?  I've been a heavy user of mail from mobile phones for long  
enough that I've done it over raw GSM data calls into modem banks  
(none of this newfangled GPRS stuff).   I've not seen a mobile phone  
in at least five years, probably more, that doesn't support IMAP.  For  
example, the Ericsson T68 supported IMAP, and that's a _long_ time ago  
in mobile phone terms.  Prior to that I used Palm Pilots with IrDA  
into various Motorola phones, but let's not go too far in archaeology.

But if you are stuck with POP3, it probably means the phone's software  
is old.  Sadly, POP3 has an unhelpful numbering scheme.

POP was introduced by RFC918 in October 1984.

It was revised to POP2 by RFC937 in Feb 1985.

Yes, for younger readers, a protocol really did go through two  
versions in five months, while only eighteen other RFCs were  
published...

POP3 was defined by RFC1081, and then modified by 1225 (helpfully  
contains no list of changes, but introduces RPOP), 1460 (again no list  
of changes, drops RPOP, introduces APOP), 1725 (draft only, removes  
LAST, adds UIDL, lots of tightening up of language) and 1939  
(standard, more tightening up), spanning from November 1988 to May  
1996.  Throughout this it stayed called `POP3', and there is no  
equivalent to the IMAP CAPABILITY to find out what it supports.  UIDL  
had been floating around as a proposal and, I think, running code  
prior to 1994 (RFC1725) and certainly prior to 1996 (RFC1939).

Given that POP3 has a chequered history when you push the semantics, I  
wouldn't trust UIDL any further than I could throw it.  It doesn't  
define an equivalent to UIDVALIDITY (Cyrus fakes it by embedding the  
mailbox creation time into each UID, so if that changes the messages  
appear new), the code in a given client is more likely to be server  
specific than RFC-compliant, and POP3 clients are inherently  
abandonware anyway.

I'd say that your users can almost certainly use IMAP, if but they  
look at the menus.  But if they can't, they are relying on Neolithic  
client implementations of a Palaeolithic protocol...

ian