Question about mail_utf8_extensions on Dovecot 2.4
Is there a reason this isn't enabled by default other than perhaps compatibility with very old systems/clients?
This sounds like a pretty useful feature if I'm understanding it correctly, and there already were enough new breaking changes with 2.4 that I don't see much downside to making this the default behavior there. What am I missing?
Thanks,
Thomas "Andy" Baugh | Software Development Engineer IV andy.baugh@webpros.com www.webpros.com
On Fri, 2026-01-23 at 21:08 +0000, Andy Baugh via dovecot wrote:
Is there a reason this isn't enabled by default other than perhaps compatibility with very old systems/clients?
...
This is an interesting question. I assume it is still marked experimental for a reason - Aki?
Many people use postfix + lmtp.
postfix has the default for "smtputf8_enable" (i.e. RFC 6531) set to "yes" for quite some time.
For things to run "smoothly", this likley requires LMTP with utf8 support as well.
The options seem to be:
* activate the experimental feature or * live with whatever happens with postfix on and lmtp off or * disable smtputf8 in postfix.
Aki and others - what do you recommend?
thanks for bringing this up Andy.
gene
On Fri, 2026-01-23 at 21:08 +0000, Andy Baugh via dovecot wrote:
Is there a reason this isn't enabled by default other than perhaps compatibility with very old systems/clients?
Configure question related to this which I did not find documented.
Since IMAP4rev2 (RFC 9051) requires utf8 in the base support, then If dovecot is built with "--enable-experimental-imap4rev2", can we assume that "--enable-experimental-mail-utf8" is not needed since it is required by imap4rev2?
I have begun a teat with IMAP4rev2 - I compiled with both flags enabled to be on the safe side.
thanks
gene
On 24/01/2026 01:01 EET Genes Lists via dovecot <dovecot@dovecot.org> wrote:
On Fri, 2026-01-23 at 21:08 +0000, Andy Baugh via dovecot wrote:
Is there a reason this isn't enabled by default other than perhaps compatibility with very old systems/clients?
Configure question related to this which I did not find documented.
Since IMAP4rev2 (RFC 9051) requires utf8 in the base support, then If dovecot is built with "--enable-experimental-imap4rev2", can we assume that "--enable-experimental-mail-utf8" is not needed since it is required by imap4rev2?
I have begun a teat with IMAP4rev2 - I compiled with both flags enabled to be on the safe side.
thanks
gene
Hi!
The reason this setting exists is that the mail utf8 support is not yet fully complete, so we want to make it possible for people to have it available (we build our CE packages with support enabled), but also being able to disable it, in case it does not work correctly.
Eventually this setting will go away.
Aki
On Sat, 2026-01-24 at 18:57 +0200, Aki Tuomi via dovecot wrote:
...
dovecot is built with "--enable-experimental-imap4rev2", can we assume that "--enable-experimental-mail-utf8" is not needed since it is required by imap4rev2?
I have begun a teat with IMAP4rev2 - I compiled with both flags enabled to be on the safe side....
Hi!
The reason this setting exists is that the mail utf8 support is not yet fully complete, so we want to make it possible for people to have it available (we build our CE packages with support enabled), but also being able to disable it, in case it does not work correctly.
Eventually this setting will go away.
Aki
Thanks you AKi.
After some initial testing, the plan here is to push to production. The predominant mail clients (evolution, fairemail on android and apple email on macos/ios) don't appear to have IMAP4rev2 support; but the UTF8 side should get some testing.
gene
participants (3)
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Aki Tuomi
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Andy Baugh
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