SMTPUTF8 error with Postfix

[salixh5]

Hey, I have a very simple Postfix install with support for EAI. When I send an email manually it looks like this:

$ telnet example.网站 25
Trying 2a01:dead:beef::1...
Connected to example.网站.
Escape character is '^]'.
220 example.xn--5tzm5g ESMTP Postfix (Debian/GNU)
EHLO localhost
250-example.xn--5tzm5g
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING
MAIL FROM:<user@localhost> SMTPUTF8
250 2.1.0 Ok
RCPT TO:<管理者@example.xn--5tzm5g>
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Date: Tue, 20 Feb 2024 17:52:59 +0100
To: 管理者@example.网站
From: user@localhost
Subject: testmail
X-Mailer: Hand-written Telnet session

Hey this is a test mail

.
250 2.0.0 Ok: queued as 8D19020BD3
QUIT
221 2.0.0 Bye
Connection closed by foreign host.

Can I do something similar with swaks? Currently it seems not to advertise SMTPUTF8 support in MAIL FROM message

$ swaks
To: 管理者@example.xn--5tzm5g
=== Trying example.xn--5tzm5g:25...
=== Connected to example.xn--5tzm5g.
<-  220 example.xn--5tzm5g ESMTP Postfix (Debian/GNU)
 -> EHLO localhost
<-  250-example.xn--5tzm5g
<-  250-PIPELINING
<-  250-SIZE 10240000
<-  250-VRFY
<-  250-ETRN
<-  250-STARTTLS
<-  250-ENHANCEDSTATUSCODES
<-  250-8BITMIME
<-  250-DSN
<-  250-SMTPUTF8
<-  250 CHUNKING
 -> MAIL FROM:<user@localhost>
<-  250 2.1.0 Ok
 -> RCPT TO:<管理者@example.xn--5tzm5g>
<** 553 5.6.7 Must declare SMTPUTF8 to send unicode address
 -> QUIT
<-  221 2.0.0 Bye
=== Connection closed with remote host.

[jetmore]

There's a patch for it in #20 and it's being considered for the next release. There's not support in the official release yet though