Subject: [Extra] IMAP4rev2, SEARCH CHARSET

From: Arnt Gulbrandsen <[email-masked]>
Date: Thu, 7 Nov 2019 11:39:03 +0100

Hi,

SEARCH CHARSET is a bit ungood now.

IMAP4rev1 used ASCII generally, and the CHARSET specification could be used 
to use something else in a search key. However, IMAP4rev2 now uses UTF-8 
generally (see section 4.3.1), and so CHARSET becomes rather odd.

I suggest obsoleting CHARSET and telling clients to use UTF-8 for searches. 
Suggested text (for 6.4.4):

"In IMAP4rev1, the client could specify the character encoding of non-ASCII 
search keys using SEARCH CHARSET. In IMAP4rev2, the client uses UTF-8 for 
all search keys, and for this reason CHARSET is now obsolete."

My question is: Obsolete CHARSET and say clients MUST NOT use it, or 
obsolete it and say that servers MUST support CHARSET UTF-8 and MAY support 
others?

Arnt

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From: Arnt Gulbrandsen <[email-masked]>
Date: Thu, 7 Nov 2019 11:49:00 +0100

I wrote:
> My question is: Obsolete CHARSET and say clients MUST NOT use 
> it, or obsolete it and say that servers MUST support CHARSET 
> UTF-8 and MAY support others?

I had a coffee. My own preference is the latter.

"Servers MUST support CHARSET UTF-8 and MAY support other encodings. 
Clients SHOULD NOT use other encodings. Note that UTF-8 is also the 
default, so selecting CHARSET UTF-8 is redundant. It is permitted for 
improved compatibility with existing IMAP4rev1 clients".

Arnt

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From: Alexey Melnikov <[email-masked]>
Date: Thu, 7 Nov 2019 10:52:42 +0000

On 07/11/2019 10:49, Arnt Gulbrandsen wrote:

>> obsolete it and say that servers MUST support CHARSET UTF-8 and MAY 
>> support others?
>
I like this too.

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From: Alexey Melnikov <[email-masked]>
Date: Thu, 7 Nov 2019 13:35:10 +0000

Hi Arnt,

> improved compatibility with existing IMAP4rev1 clients".

I used something very close to your text.

Best Regards,

Alexey