I will wait for the next ActiveSync release, maybe its how I applied 
the patch.

Don't know what to tell you. Works here after the change, breaks if 
it's reverted.

No. It will actually be 2.21.0 now due to some changes I needed to 
make for another bug. I'm waiting to be able to test those other 
changes before releasing.

Manually applied commit: 
http://github.com/horde/horde/commit/5442476c0570d3ad18ab52ba6bfb54a91e6a4414
Issue is worse after change, almost all HTML emails do not show iOS.

Any updates on when 2.20.6 will be available?

Thank you, I will test when its available via pear.

Horde_ActiveSync 2.20.6

Changes have been made in Git (master):

commit 5442476c0570d3ad18ab52ba6bfb54a91e6a4414
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Fri Dec 5 09:46:56 2014 -0500

     Bug: 13728 Don't overwrite the MIME part's MIME headers.

  .../lib/Horde/ActiveSync/Imap/Adapter.php          |    9 +++++++--
  1 files changed, 7 insertions(+), 2 deletions(-)

http://github.com/horde/horde/commit/5442476c0570d3ad18ab52ba6bfb54a91e6a4414

So,
Is there anyway to make the Horde_Mime more accepting again?
Or anyway to set ActiveSync to only forward the HTML parts and not the 
Plain text parts?

Screenshot 2.5.2 (working)

Screenshot 2.5.4 (latest)

Last Example.
Attached in the source

There were some recent changes to Horde_Mime which made it less 
accepting of these types of structure errors.

I just find it curious that both those example emails show correctly 
in Android ( as you explained its how the emails are read by the 
client ) and also in 2.5.2 the emails show correctly in iOS.

Yeah, I have that enabled, so there are no viewable parts.

This issue I may be able to work around in code, but not the previous example.

I have no issue viewing it on my install,
I have 'inline' => true, set in imp/config/mime_drivers.php though.

...and this email doesn't even display properly in IMP for me. It's 
declared as a multiplart/alternative part but contains only a single 
part (text/html).

Uploading this time, sorry

No attachment.

Screenshot of example2.eml

Another example email, this one seems to show the code,
Screenshot coming next

Can you provide another one of these emails? Preferably one that is 
not mis-structured?

Just to clear up,
I am only seeing this issue on 2.5.3+
I run up a test server with 2.5.2 and this email displays correctly on iOS.
Also this is happening on around 20% of my emails, most of those being 
from mailing lists.

Exactly. This isn't raw HTML, it's a display of both the text/plain 
part and the text/html part for the reasons I just posted.

The issue is the way the email is structured. It is structured as a 
multipart/mixed message, but contains only a single part on the first 
level. This part contains a multipart/alternative message that iOS 
sees as a single part since there is no other multipart/mixed part.

Manually restructuring the email to remove the multipart/mixed part 
causes the message to display normally. There is nothing Horde can do 
to work around this (short of munging the MIME data which we won't do) 
  since it's the client's job to determine which MIME part to display.

Part2

Attached are screen shots of what I am seeing,
Part1

For me, on iOS, it shows both the plain and HTML parts for some 
reason, but no raw HTML code. Other HTML emails display normally.

No change,
Updated to Horde_Mime-2.6.0 + Horde_Stream-1.6.2 + Horde_ActiveSync-2.20.5

Attached copy of email ( correctly i hope this time )

This displays correctly on IMP and on Android devices, it seems to be 
only iOS.
Tested removing ActiveSync Device, removing the account and setting up 
from scratch, same result.
I might add I am running iOS 8.1 on all my iOS devices, so can not 
test on iOS 7. I did not have an issue after the iOS update, only 
after the Horde_Webmail 2.5.2 to 5.2.3 upgrade.

Also, please see if this is fixed now that Bug: 13711 is fixed.

This is not an email, it's just an HTML document.

I would need the actual email source to test.

Hi,
I have saved the email (which shows correctly in IMP) and attached it.

Possibly related to Bug: 13711.

Either way, I would need a copy of an email that exhibits this behavior.

Since updating to ActiveSync 2.20.4 HTML some emails are showing as 
HTML code rather than showing correctly on iOS devices.