Я задал вопрос здесь: Отправка электронной почты с приглашением календаря и HTML не отображается правильно И получил указание сделать еще одну запись с HTML и содержимым сообщений, так что вот оно.HTML, содержащий текст и изображения, выглядит следующим образом:
<br><div class="dagsordenMødeDato"> Her er dagsordenen for mødet 10-10-2018 14:45:00 </div><br>
<br><ul class="dagsordenListe">
<li>Leasing til dig</li>
<li>Pension</li><li>Garantkunde</li>
<li>Dine fordele</li>
</ul><br>
<div class="bekrivelseAfVedhæftning">Jeg har vedhæftet et dokument der kommer med nærmere detaljer omkring disse, så du kan danne dig et indblik i hvad det hele drejer sig om.</div>
<a href="https://www.sparthy.dk/"><img src=cid:raadgiverID alt="medarbejder"></p></a>
<a href="https://www.sparthy.dk/om-sparekassen/nyheder-generelt/1912-garantmoder-2018"><img style="border: 0;" src=cid:kampagneID alt="kampagne"></a>
Это письмо работает безупречно в приложении «Почта» для Iphone:
MIME-Version: 1.0
From: bob <mailDemo@hotmail.com>
To: Client Name <client@gmail.com>
Date: 8 Oct 2018 08:13:32 +0200
Subject: Send Calendar Appointment Email
X-MIMETrack: Itemize by SMTP Server on SDC-SMTP-GTW02/SDC-SMTP-GTW(Release9.0.1FP9 HF60|September 14, 2017) at 08-10-2018 08:13:31, Serialize by Router on SDC-MTA01/SDCU-MTA(Release 9.0.1FP9 HF60|September 14, 2017) at 08-10-2018 08:13:31
Message-ID: <OFA857A7C6.BD466C36-ONC1258320.0022325E@fejl.sdc.dk>
Content-Type: multipart/alternative; boundary=--boundary_0_edc4d002-6677-4eef-810a-9a8ca7cf11dd
----boundary_0_edc4d002-6677-4eef-810a-9a8ca7cf11dd
Content-Type: text/calendar; charset=utf-8; method=REQUEST; name=Invitation.ics
Content-Transfer-Encoding: quoted-printable
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SparThy moedebooking//
CALSCALE:GREGORIAN
METHOD:REQUEST
BEGIN:VEVENT
DTSTART:20181111T190000
DTEND:20181111T200000
DTSTAMP:20181005T095500
UID:ae6ad30a-cf08-48a3-9e30-c284c917159d
ORGANIZER;CN=3D3DSvendbent:mailto:m=3DC3=3DB8debooking@sparthy.dk
DESCRIPTION:hestearsadasdkmbdfkmbkmg ICSTEKST
LOCATION:Sparekassen Thy
STATUS:CONFIRMED
SUMMARY:John - M=3DC3=3DB8de i banken
TRANSP:OPAQUE
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:event reminder
TRIGGER:-PT25M
END:VALARM
END:VEVENT
END:VCALENDAR
----boundary_0_edc4d002-6677-4eef-810a-9a8ca7cf11dd
Content-Type: multipart/related; boundary=--boundary_1_dedff296-75eb-4f5f-a8bc-90df20dcf880; type="text/html"
----boundary_1_dedff296-75eb-4f5f-a8bc-90df20dcf880
Content-Transfer-Encoding: base64
Content-Type: text/html; charset=utf-8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----boundary_1_dedff296-75eb-4f5f-a8bc-90df20dcf880
Content-Type: image/jpeg; name=Raadgiver.jpg
Content-ID: <raadgiverID>
Content-Transfer-Encoding: base64
----boundary_1_dedff296-75eb-4f5f-a8bc-90df20dcf880
Content-Type: image/jpeg; name=Kampagne.jpg
Content-ID: <kampagneID>
Content-Transfer-Encoding: base64
----boundary_1_dedff296-75eb-4f5f-a8bc-90df20dcf880--
----boundary_0_edc4d002-6677-4eef-810a-9a8ca7cf11dd--
В то время как это письмо работает в Office365 /Outlook:
MIME-Version: 1.0
From: bob <mailDemo@hotmail.com>
To: Client Name <Client@gmail.com>
Date: 8 Oct 2018 09:24:31 +0200
Subject: Send Calendar Appointment Email
X-MIMETrack: Itemize by SMTP Server on SDC-SMTP-GTW02/SDC-SMTP-GTW(Release 9.0.1FP9 HF60|September 14, 2017) at 08-10-2018 09:24:31, Serialize by Router on SDC-MTA01/SDCU-MTA(Release 9.0.1FP9 HF60|September 14, 2017) at 08-10-2018 09:24:31
Message-ID: <OFCFE84C3C.BB7738A8-ONC1258320.0028B286@fejl.sdc.dk>
Content-Type: multipart/alternative; boundary=--boundary_0_346859df-960e-4ba3-a67f-242254860f00
----boundary_0_346859df-960e-4ba3-a67f-242254860f00
Content-Type: multipart/related; boundary=--boundary_1_be0608b8-7945-456e- b6a2-b6245778b0a0; type="text/html"
----boundary_1_be0608b8-7945-456e-b6a2-b6245778b0a0
Content-Transfer-Encoding: base64
Content-Type: text/html; charset=utf-8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----boundary_1_be0608b8-7945-456e-b6a2-b6245778b0a0
Content-Type: image/jpeg; name=Raadgiver.jpg
Content-ID: <raadgiverID>
Content-Transfer-Encoding: base64
----boundary_1_be0608b8-7945-456e-b6a2-b6245778b0a0
Content-Type: image/jpeg; name=Kampagne.jpg
Content-ID: <kampagneID>
Content-Transfer-Encoding: base64
----boundary_1_be0608b8-7945-456e-b6a2-b6245778b0a0--
----boundary_0_346859df-960e-4ba3-a67f-242254860f00
Content-Type: text/calendar; charset=utf-8; method=REQUEST; name=Invitation.ics
Content-Transfer-Encoding: quoted-printable
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SparThy moedebooking//
CALSCALE:GREGORIAN
METHOD:REQUEST
BEGIN:VEVENT
DTSTART:20181111T190000
DTEND:20181111T200000
DTSTAMP:20181005T095500
UID:ae6ad30a-cf08-48a3-9e30-c284c917159d
ORGANIZER;CN=3D3DSvendbent:mailto:m=3DC3=3DB8debooking@sparthy.dk
DESCRIPTION:hestearsadasdkmbdfkmbkmg ICSTEKST
LOCATION:Sparekassen Thy
STATUS:CONFIRMED
SUMMARY:John - M=3DC3=3DB8de i banken
TRANSP:OPAQUE
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:event reminder
TRIGGER:-PT25M
END:VALARM
END:VEVENT
END:VCALENDAR
----boundary_0_346859df-960e-4ba3-a67f-242254860f00--
Оба образца mime взяты из копии, отправленной на gmail.com. Gmail.com/appversions из Gmail, похоже, правильно показывает почту независимо от того, какой подход я выбрал.
Заранее спасибо.