[imp] (no subject)

[Nethub Online]

Hi all,

When sending an email from Horde IMP, we encountered a problem. The email
attachment with a UTF-8 encoded file name (such as Japanese,
Chinese...etc.) cannot be displayed properly in some email softwares (e.g.
Untitled attachment , utf-8"%E3%...%83%BC.txt).

Is it a bug? Since rarely encountered problems with the software of 2
different companies, we have tested the following software will cause
problems, can someone help?

Gmail App (Android) : https://ibb.co/kmz7Y5z
Outlook 2019 (Windows) : https://ibb.co/6nDNVq4

Below is the source code of the Email:

Return-Path: <test at mail-test.net>
X-Original-To: test at mail-test.net
Delivered-To: test at mail-test.net
Received: by mail-test.net (Postfix, from userid 991)
    id D7CA0CB40002; Tue, 24 Nov 2020 04:56:41 +0000 (UTC)
Received: from 123.123.123.123
 (123.123.123.123) by
 webmail.mail-test.net (Horde Framework) with HTTP; Tue, 24 Nov 2020
 12:56:41 +0800
Date: Tue, 24 Nov 2020 12:56:41 +0800
Message-ID: <
20201124125641.Horde.DEJq4YpEDpX5nEm0DP_QP0B at webmail.mail-test.net>
From: test at mail-test.net
To: test at mail-test.net
Subject: test
User-Agent: Horde Application Framework 5
Content-Type: multipart/mixed; boundary="=_a8jQtOkqJdunsBazNSPpOfO"
MIME-Version: 1.0

This message is in MIME format.

--=_a8jQtOkqJdunsBazNSPpOfO
Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes
Content-Disposition: inline


test

--=_a8jQtOkqJdunsBazNSPpOfO
Content-Type: text/plain; name*=utf-8''%E3%81%AF%E3%82%8D%E3%83%BC.txt
Content-Disposition: attachment; size=4;
 filename*=utf-8''%E3%81%AF%E3%82%8D%E3%83%BC.txt

Test
--=_a8jQtOkqJdunsBazNSPpOfO--