Hi Michael,

thanks for the clear comment. However, I would suggest to update the 
installation instruction accordingly, they still recommend sendmail:
"Horde uses sendmail, or a program that implements the sendmail(8) API 
(as included with postfix, qmail, and exim, among others). If your 
system does not already have a full mail transport with a sendmail 
interface, you can configure Horde to speak directly with a remote 
SMTP server."
(http://www.horde.org/apps/horde/docs/INSTALL)
That's why I used sendmail and ran into this precise problem

I switched to local SMTP to transfer mails to Exim. As my multiple 
smarthost configuration seems to keep working without tinkering the 
transition was astonishingly painless.
I hope that for other users switching away from sendmail will be just as easy.

Thanks for the soultion

Changes have been made in Git for this ticket:

[mms] Add 'sendmail_eol' configuration parameter (Bug #10930).
Also, make very clear in documentation that people should be using SMTP,
not sendmail.

  5 files changed, 35 insertions(+), 11 deletions(-)
http://git.horde.org/horde-git/-/commit/cd1b5793c0e771eb871f7b4295dbcab580bb5929

Horde_Mail isn't broken.  Verified with unit tests - the entire 
message is correctly sent with the proper linebreaks in all parts of 
the message.

The fix from Ticket #10696 was wrong.  There is no expectation that we 
should be sending canonical CRLF linebreaks to the sendmail binary - 
since this is a SMTP convention.  Sendmail != SMTP.

Instead, we are piping output to a local program.  As such, we should 
be separating lines with the OS line separator (PHP_EOL).

Thus, there is no way to be automatically compatible with all sendmail 
binaries.  The current behavior is the more correct of the two (see 
below) so that is what we will use going forward.

See, e.g.:
http://www.php.net/manual/en/function.mail.php
https://bugs.php.net/bug.php?id=15841

I guess we should allow configuration of the separator to workaround 
this.  But the more correct solution is to use SMTP.

Changes have been made in Git for this ticket:

Bug #10930: additional tests
Better test for wrapped headers.

  1 files changed, 13 insertions(+), 1 deletions(-)
http://git.horde.org/horde-git/-/commit/b4c1b3750b242550d62a9f8f08bd875e2e5fe64d

You REALLY need to use SMTP.  Nobody should be using sendmail.  For 
precisely this issue - since these fixes have verifiable corrected 
other broken sendmail issues, and the test suite proves this.

Sorry,
I use the sendmail substitute that Exim provides

Downgraded to 1.0.2 and things work again, thanks...

I use Exim 4.75

Which Mailer configuration do you use? Sendmail? If yes, try 
downgrading Horde_Mail.

Testmessage looks like this (I think it wasn´t a problem with code 
pages but with an incompatible type of type of end of line character):

Return-path: <x@x.de>
Envelope-to: twilek@localhost
Delivery-date: Wed, 18 Jan 2012 08:30:06 +0100
Received: from localhost ([127.0.0.1] helo=x.x.info)
        by x.x.info with esmtp (Exim 4.75)
        (envelope-from <x@x.de>)
        id 1RnPy6-0008Rv-Cw
        for twilek@localhost; Wed, 18 Jan 2012 08:30:06 +0100
Delivered-To: GMX delivery to x@gmx.de
Received: from pop.gmx.net [212.227.17.185]
        by x.x.info with POP3 (fetchmail-6.3.21)
        for <twilek@localhost> (single-drop); Wed, 18 Jan 2012 08:30:02 +0100 (CET)
Received: (qmail invoked by alias); 18 Jan 2012 07:21:08 -0000
Received: from moutng.x.de (EHLO moutng.xr.de) [212.227.126.186]
   by mx0.gmx.net (mx118) with SMTP; 18 Jan 2012 08:21:08 +0100
Received: from x.x.info (x.de [87.106.21.253])
        by mrelayeu.x.de (node=mreu3) with ESMTP (Nemesis)
        id 0M8X4h-1SZaTI3jPf-00wECi; Wed, 18 Jan 2012 08:21:07 +0100
Received: from www-data by x.x.info with local (Exim 4.75)
        (envelope-from <x@x.de>)
        id 1RnPpO-0008Q9-EU
        for x@gmx.de; Wed, 18 Jan 2012 08:21:07 +0100
Received: from ip-0-0-0-0.x.de
  (ip-0-0-0-0.x.de [178.200.154.165]) by www.x.de
  (Horde Framework) with HTTP; Wed, 18 Jan 2012 08:21:02 +0100
  Date: Wed, 18 Jan 2012 08:21:02 +0100
  Message-ID: <20120118082102.Horde.O0cibOmkpHVPFnLeYM0n3UA@www.x.de>
  From: x x <x@x.de>
  To: x@gmx.de
  Subject: Test
  User-Agent: Internet Messaging Program (IMP) H4 (5.0.18)
  Content-Type: text/plain; charset=ISO-8859-1; format=flowed; DelSp=Yes
  MIME-Version: 1.0
  Content-Disposition: inline


  Test
Message-Id: <E1RnPpO-0008Q9-EU@x.x.info>
From: www-data <x@x.de>
Date: Wed, 18 Jan 2012 08:21:02 +0100
X-Provags-ID: V02:K0:H8wPy+icl4fWeUGU7Pcpxdu9HwU7DEW1s9pjkekKRaN
  N61QuZkvlxbiOuGd1fBr+fUM0YUpSKEmNfw8IZFx8byBEBgcjw
  Mqr9D+hdwG70B4D6YBAVn/CCPzDrl9qNQ0zbtKiXpAS1jLPJfA
  cxR7D0uhBj0szU7hfXATBZq4zvcK4zZOenYWGXldLytfP3hbK1
  e+KhANlj1V5WYfnR1/3xDTEJ8ryucOqZhEIGvlbkEIiKpdDdn/
  kRrf18U94B7LxtfF360fPPq+4hd1f1s3PTU2g88Td/LgdqGMs9
  EH3MX5jeL2z1Sq/qr9TNLZw6B1D6c0zOY7r4qvNDH3m39LgD+w
  WgAUgtjm4tjLsTQb88hVUnuCHkpYd6JpJONNlIVgfaHa6/4mWq
  Y3twmyqaOwz2jZ5QQ6CW+uxCwNcBop5Z5c=
X-GMX-Antivirus: 0 (no virus found)
X-GMX-Antispam: -2 (not scanned, spam filter disabled);
  Detail=5D7Q89H36p4L00VTXC6D4q0N+AH0PUCnKGJbGgJLbSXk30NezpdxUg==V1;
X-SA-Exim-Connect-IP: 127.0.0.1
X-SA-Exim-Mail-From: x@x.de
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
        x.x.info
X-Spam-Level:
X-Spam-Status: No, score=-96.3 required=5.0 tests=AWL,BAYES_00,EMPTY_MESSAGE,
        MISSING_HEADERS,MISSING_SUBJECT,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS,
        USER_IN_WHITELIST autolearn=no version=3.3.1
X-SA-Exim-Version: 4.2.1 (built Mon, 22 Mar 2010 06:26:47 +0000)
X-SA-Exim-Scanned: Yes (on x.x.info)

Example messages?

I have just noticed that Imp also seems to have proplems showing 
Base64 encoded text messages. An jpg Mime encoded in the same Message 
showed up correctly. I don´t know wether this is associated or 
something different.

Since last nights update an old bug seems to be back (the one with 
headers being added at the end of the message). It had something to do 
with the encoding page if I remember correctly. The end of it is that 
Imp will send garbled messages without content (The content is still 
there, but as there are header lines after the message body email 
programs and horde itself do not show it).