diff --git a/HISTORY.rst b/HISTORY.rst
index a8a024b7ff..9400d6e27d 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -146,6 +146,7 @@
 - Improve rendering of the details form.
 - Update rendering of the readonly multiselect widget to conform to Django's updated field class interface.
 - Add warning when using SQLite as the database backend.
+- Use Mailgun's flanker library to process the email sources.
 
 2.7.3 (2017-09-11)
 ==================
diff --git a/docs/releases/3.0.rst b/docs/releases/3.0.rst
index e6d1a0986c..dfead2a67b 100644
--- a/docs/releases/3.0.rst
+++ b/docs/releases/3.0.rst
@@ -349,6 +349,15 @@ SQLite. The results are duplicated documents, frequency database locked errors,
 among other issues. Suggested database backends are PostgreSQL and MySQL
 (or MariaDB) using a transaction aware storage engine like InnoDB.
 
+Received email processing
+-------------------------
+Parsing email messages is a complex task. To increase compatibility with the
+many interpretations of the standards that govern email messaging, Mayan EDMS
+now uses Mailgun's flanker library (https://github.com/mailgun/flanker).
+Thanks to flanker, Mayan EDMS now gains new capabilities when it comes to
+parsing incoming email. For example, in addition to mail attachments, it is now
+possible to process files included in emails as inline content.
+
 Other changes worth mentioning
 ------------------------------
 - Add Makefile target to check the format of the README.rst file.
diff --git a/mayan/apps/sources/classes.py b/mayan/apps/sources/classes.py
index 4b9ccc352c..3fcf32e4c2 100644
--- a/mayan/apps/sources/classes.py
+++ b/mayan/apps/sources/classes.py
@@ -29,14 +29,6 @@ class SourceUploadedFile(File):
         self.extra_data = extra_data
 
 
-class Attachment(File):
-    def __init__(self, part, name):
-        self.name = name
-        self.file = PseudoFile(
-            BytesIO(part.get_payload(decode=True)), name=name
-        )
-
-
 @python_2_unicode_compatible
 class StagingFile(object):
     """
diff --git a/mayan/apps/sources/models.py b/mayan/apps/sources/models.py
index 21b6ecc710..3b029bfd4c 100644
--- a/mayan/apps/sources/models.py
+++ b/mayan/apps/sources/models.py
@@ -9,6 +9,7 @@ import os
 import poplib
 import subprocess
 
+from flanker import mime
 import sh
 import yaml
 
@@ -21,7 +22,9 @@ from django.core.exceptions import ValidationError
 from django.core.files import File
 from django.core.files.base import ContentFile
 from django.db import models, transaction
-from django.utils.encoding import force_text, python_2_unicode_compatible
+from django.utils.encoding import (
+    force_str, force_text, python_2_unicode_compatible
+)
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
 
@@ -37,7 +40,7 @@ from documents.settings import setting_language
 from metadata.api import set_bulk_metadata
 from metadata.models import MetadataType
 
-from .classes import Attachment, PseudoFile, SourceUploadedFile, StagingFile
+from .classes import PseudoFile, SourceUploadedFile, StagingFile
 from .exceptions import SourceException
 from .literals import (
     DEFAULT_INTERVAL, DEFAULT_POP3_TIMEOUT, DEFAULT_IMAP_MAILBOX,
@@ -573,11 +576,7 @@ class EmailBaseModel(IntervalBaseModel):
         return ''.join(header_sections)
 
     @staticmethod
-    def process_message(source, message):
-        counter = 1
-        email = message_from_string(message)
-        metadata_dictionary = {}
-
+    def process_message(source, message_text):
         if source.subject_metadata_type:
             metadata_dictionary[
                 source.subject_metadata_type.name
@@ -588,29 +587,22 @@ class EmailBaseModel(IntervalBaseModel):
                 source.from_metadata_type.name
             ] = EmailBaseModel.getheader(email['From'])
 
-        for part in email.walk():
-            disposition = part.get('Content-Disposition', 'none')
-            logger.debug('Disposition: %s', disposition)
+        counter = 1
+        metadata_dictionary = {}
 
-            if disposition.startswith('attachment'):
-                raw_filename = part.get_filename()
+        message = mime.from_string(force_str(message_text))
 
-                if raw_filename:
-                    filename = collapse_rfc2231_value(raw_filename)
-
-                    # Decode base64 encoded filename
-                    # https://stackoverflow.com/a/21859258/1364435
-                    if decode_header(filename)[0][1] is not None:
-                        filename = str(decode_header(filename)[0][0]).decode(decode_header(filename)[0][1])
-
-                else:
-                    filename = _('attachment-%i') % counter
-                    counter += 1
-
-                logger.debug('filename: %s', filename)
-
-                with Attachment(part, name=filename) as file_object:
-                    if filename == source.metadata_attachment_name:
+        # Messages are tree based, do nested processing of message parts until
+        # a message with no children is found, then work out way up.
+        if message.parts:
+            for part in message.parts:
+                EmailBaseModel.process_message(source=source, message_text=part.to_string())
+        else:
+            # Treat inlines as attachments, both are extracted and saved as
+            # documents
+            if message.is_attachment() or message.is_inline():
+                with ContentFile(content=message.body, name=message.detected_file_name) as file_object:
+                    if message.detected_file_name == source.metadata_attachment_name:
                         metadata_dictionary = yaml.safe_load(
                             file_object.read()
                         )
@@ -620,7 +612,7 @@ class EmailBaseModel(IntervalBaseModel):
                     else:
                         document = source.handle_upload(
                             document_type=source.document_type,
-                            file_object=file_object, label=filename,
+                            file_object=file_object, label=message.detected_file_name,
                             expand=(
                                 source.uncompress == SOURCE_UNCOMPRESS_CHOICE_Y
                             )
@@ -631,25 +623,24 @@ class EmailBaseModel(IntervalBaseModel):
                                 metadata_dictionary=metadata_dictionary
                             )
             else:
-                logger.debug('No Content-Disposition')
+                # If it is not an attachment then it should be a body message part.
+                # Another option is to use message.is_body()
+                if message.detected_content_type == 'text/html':
+                    label = 'email_body.html'
+                else:
+                    label = 'email_body.txt'
 
-                content_type = part.get_content_type()
-
-                logger.debug('content_type: %s', content_type)
-
-                if content_type == 'text/plain' and source.store_body:
-                    content = part.get_payload(decode=True).decode(part.get_content_charset())
-                    with ContentFile(content=content, name='email_body.txt') as file_object:
-                        document = source.handle_upload(
-                            document_type=source.document_type,
-                            file_object=file_object,
-                            expand=SOURCE_UNCOMPRESS_CHOICE_N, label='email_body.txt',
+                with ContentFile(content=message.body, name=label) as file_object:
+                    document = source.handle_upload(
+                        document_type=source.document_type,
+                        file_object=file_object,
+                        expand=SOURCE_UNCOMPRESS_CHOICE_N
+                    )
+                    if metadata_dictionary:
+                        set_bulk_metadata(
+                            document=document,
+                            metadata_dictionary=metadata_dictionary
                         )
-                        if metadata_dictionary:
-                            set_bulk_metadata(
-                                document=document,
-                                metadata_dictionary=metadata_dictionary
-                            )
 
 
 class POP3Email(EmailBaseModel):
@@ -692,7 +683,7 @@ class POP3Email(EmailBaseModel):
             complete_message = '\n'.join(mailbox.retr(message_number)[1])
 
             EmailBaseModel.process_message(
-                source=self, message=complete_message
+                source=self, message_text=complete_message
             )
             mailbox.dele(message_number)
 
@@ -737,7 +728,7 @@ class IMAPEmail(EmailBaseModel):
                 logger.debug('message_number: %s', message_number)
                 status, data = mailbox.fetch(message_number, '(RFC822)')
                 EmailBaseModel.process_message(
-                    source=self, message=data[0][1]
+                    source=self, message_text=data[0][1]
                 )
                 mailbox.store(message_number, '+FLAGS', '\\Deleted')
 
diff --git a/mayan/apps/sources/tests/literals.py b/mayan/apps/sources/tests/literals.py
index 9bc4521ebe..37acf777de 100644
--- a/mayan/apps/sources/tests/literals.py
+++ b/mayan/apps/sources/tests/literals.py
@@ -1,5 +1,113 @@
 from __future__ import unicode_literals
 
+TEST_EMAIL_ATTACHMENT_AND_INLINE='''Subject: Test 03: inline and attachments
+To: Renat Gilmanov
+Content-Type: multipart/mixed; boundary=001a11c24d809f1525051712cc78
+
+--001a11c24d809f1525051712cc78
+Content-Type: multipart/related; boundary=001a11c24d809f1523051712cc77
+
+--001a11c24d809f1523051712cc77
+Content-Type: text/html; charset=UTF-8
+Content-Transfer-Encoding: quoted-printable
+
+<div dir=3D"ltr">Lorem ipsum dolor sit amet, consectetur adipiscing elit. P=
+ellentesque odio urna, bibendum eu ultricies in, dignissim in magna. Vivamu=
+s risus justo, viverra sed dapibus eu, laoreet eget erat. Sed pretium a urn=
+a id pulvinar.<br><br><img src=3D"cid:ii_ia6yyemg0_14d9636d8ac7a587" height=
+=3D"218" width=3D"320"><br>=E2=80=8B<br>Cras eu velit ac purus feugiat impe=
+rdiet nec sit amet ipsum. Praesent gravida lobortis justo, nec tristique ve=
+lit sagittis finibus. Suspendisse porta ante id diam varius, in cursus ante=
+ luctus. Aenean a mollis mi. Pellentesque accumsan lacus sed erat vulputate=
+, et semper tellus condimentum.<br><br>Best regards</div>
+
+--001a11c24d809f1523051712cc77
+Content-Type: image/png; name="test-01.png"
+Content-Disposition: inline; filename="test-01.png"
+Content-Transfer-Encoding: base64
+Content-ID: <ii_ia6yyemg0_14d9636d8ac7a587>
+X-Attachment-Id: ii_ia6yyemg0_14d9636d8ac7a587
+
+iVBORw0KGgoAAAANSUhEUgAAAUAAAADaCAYAAADXGps7AAAABHNCSVQICAgIfAhkiAAAAAlwSFlz
+AAALewAAC3sBSRnwgAAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ5vuPBoAAALnSURB
+...
+QCDLAIEsAwSyDBDIMkAgywCBLAMEsgwQyDJAIMsAgSwDBLIMEMgyQCDLAIEsAwSyDBDIMkAg6wK+
+4gU280YtuwAAAABJRU5ErkJggg==
+--001a11c24d809f1523051712cc77--
+--001a11c24d809f1525051712cc78
+Content-Type: image/png; name="test-02.png"
+Content-Disposition: attachment; filename="test-02.png"
+Content-Transfer-Encoding: base64
+X-Attachment-Id: f_ia6yymei1'''
+TEST_EMAIL_BASE64_FILENAME = '''From: noreply@example.com
+To: test@example.com
+Subject: Scan to E-mail Server Job
+Date: Tue, 23 May 2017 23:03:37 +0200
+Message-Id: <00000001.465619c9.1.00@BRN30055CCF4D76>
+Mime-Version: 1.0
+Content-Type: multipart/mixed;
+    boundary="RS1tYWlsIENsaWVudA=="
+X-Mailer: E-mail Client
+
+This is multipart message.
+
+--RS1tYWlsIENsaWVudA==
+Content-Type: text/plain; charset=iso-8859-1
+Content-Transfer-Encoding: quoted-printable
+
+Sending device cannot receive e-mail replies.
+--RS1tYWlsIENsaWVudA==
+Content-Type: text/plain
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment; filename="=?UTF-8?B?QW1wZWxtw6RubmNoZW4udHh0?="
+
+SGFsbG8gQW1wZWxtw6RubmNoZW4hCg==
+
+--RS1tYWlsIENsaWVudA==--'''
+
+TEST_EMAIL_NO_CONTENT_TYPE = '''MIME-Version: 1.0
+Received: by 10.0.0.1 with HTTP; Mon, 9 Apr 2018 00:00:00 -0400 (AST)
+X-Originating-IP: [10.0.0.1]
+Date: Mon, 9 Apr 2018 0:00:0 -0400
+Delivered-To: test-sender@example.com
+Message-ID: <CAEAsyCbSF1Bk7CBuu6zp3Qs8=j2iUkNi3dPkGe6z40q4dmaogQ@mail.gmail.com>
+Subject: Test message with no content type
+From: Test Sender <test-sender@example.com>
+To: test-receiver@example.com
+
+Test email without a content type'''
+TEST_EMAIL_NO_CONTENT_TYPE_STRING = 'Test email without a content type'
+TEST_EMAIL_INLINE_IMAGE = '''Subject: Test 01: inline only
+To: Renat Gilmanov
+Content-Type: multipart/related; boundary=089e0149bb0ea4e55c051712afb5
+
+--089e0149bb0ea4e55c051712afb5
+Content-Type: text/html; charset=UTF-8
+Content-Transfer-Encoding: quoted-printable
+
+<div dir=3D"ltr">Lorem ipsum dolor sit amet, consectetur adipiscing elit. P=
+ellentesque odio urna, bibendum eu ultricies in, dignissim in magna. Vivamu=
+s risus justo, viverra sed dapibus eu, laoreet eget erat. Sed pretium a urn=
+a id pulvinar.<br><br><img src=3D"cid:ii_ia6yo3z92_14d962f8450cc6f1" height=
+=3D"218" width=3D"320"><br>=E2=80=8B<br>Cras eu velit ac purus feugiat impe=
+rdiet nec sit amet ipsum. Praesent gravida lobortis justo, nec tristique ve=
+lit sagittis finibus. Suspendisse porta ante id diam varius, in cursus ante=
+ luctus. Aenean a mollis mi. Pellentesque accumsan lacus sed erat vulputate=
+, et semper tellus condimentum.<br><br>Best regards<br></div>
+
+--089e0149bb0ea4e55c051712afb5
+Content-Type: image/png; name="test-01.png"
+Content-Disposition: inline; filename="test-01.png"
+Content-Transfer-Encoding: base64
+Content-ID: <ii_ia6yo3z92_14d962f8450cc6f1>
+X-Attachment-Id: ii_ia6yo3z92_14d962f8450cc6f1
+
+iVBORw0KGgoAAAANSUhEUgAAAUAAAADaCAYAAADXGps7AAAABHNCSVQICAgIfAhkiAAAAAlwSFlz
+AAALewAAC3sBSRnwgAAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ5vuPBoAAALnSURB
+...
+QCDLAIEsAwSyDBDIMkAgywCBLAMEsgwQyDJAIMsAgSwDBLIMEMgyQCDLAIEsAwSyDBDIMkAg6wK+
+4gU280YtuwAAAABJRU5ErkJggg==
+--089e0149bb0ea4e55c051712afb5--'''
 TEST_SOURCE_LABEL = 'test source'
 TEST_SOURCE_UNCOMPRESS_N = 'n'
 TEST_STAGING_PREVIEW_WIDTH = 640
diff --git a/mayan/apps/sources/tests/test_models.py b/mayan/apps/sources/tests/test_models.py
index 8aa7d70b98..d322e64e01 100644
--- a/mayan/apps/sources/tests/test_models.py
+++ b/mayan/apps/sources/tests/test_models.py
@@ -16,6 +16,12 @@ from documents.tests import (
 from ..literals import SOURCE_UNCOMPRESS_CHOICE_Y
 from ..models import WatchFolderSource, WebFormSource, EmailBaseModel
 
+from .literals import (
+    TEST_EMAIL_ATTACHMENT_AND_INLINE, TEST_EMAIL_BASE64_FILENAME,
+    TEST_EMAIL_INLINE_IMAGE, TEST_EMAIL_NO_CONTENT_TYPE,
+    TEST_EMAIL_NO_CONTENT_TYPE_STRING
+)
+
 
 @override_settings(OCR_AUTO_OCR=False)
 class UploadDocumentTestCase(BaseTestCase):
@@ -119,53 +125,68 @@ class CompressedUploadsTestCase(BaseTestCase):
         )
 
 
-test_email = """From: noreply@example.com
-To: test@example.com
-Subject: Scan to E-mail Server Job
-Date: Tue, 23 May 2017 23:03:37 +0200
-Message-Id: <00000001.465619c9.1.00@BRN30055CCF4D76>
-Mime-Version: 1.0
-Content-Type: multipart/mixed;
-    boundary="RS1tYWlsIENsaWVudA=="
-X-Mailer: E-mail Client
-
-This is multipart message.
-
---RS1tYWlsIENsaWVudA==
-Content-Type: text/plain; charset=iso-8859-1
-Content-Transfer-Encoding: quoted-printable
-
-Sending device cannot receive e-mail replies.
---RS1tYWlsIENsaWVudA==
-Content-Type: text/plain
-Content-Transfer-Encoding: base64
-Content-Disposition: attachment; filename="=?UTF-8?B?QW1wZWxtw6RubmNoZW4udHh0?="
-
-SGFsbG8gQW1wZWxtw6RubmNoZW4hCg==
-
---RS1tYWlsIENsaWVudA==--"""
-
-
-class SourceStub():
-    subject_metadata_type = None
-    from_metadata_type = None
-    metadata_attachment_name = None
-    document_type = None
-    uncompress = None
-    store_body = False
-    label = ""
-
-    def handle_upload(self, file_object, description=None, document_type=None, expand=False, label=None, language=None,
-                      metadata_dict_list=None, metadata_dictionary=None, tag_ids=None, user=None):
-        self.label = label
-
-
+@override_settings(OCR_AUTO_OCR=False)
 class EmailFilenameDecodingTestCase(BaseTestCase):
-    """
-    Test decoding of base64 encoded e-mail attachment filename.
-    """
+    def setUp(self):
+        super(EmailFilenameDecodingTestCase, self).setUp()
+        self.document_type = DocumentType.objects.create(
+            label=TEST_DOCUMENT_TYPE_LABEL
+        )
 
-    def test_decode_email_encoded_filename(self):
-        source_stub = SourceStub()
-        EmailBaseModel.process_message(source_stub, test_email)
-        self.assertEqual(source_stub.label, u'Ampelm\xe4nnchen.txt')
+    def tearDown(self):
+        self.document_type.delete()
+        super(EmailFilenameDecodingTestCase, self).tearDown()
+
+    def _create_email_source(self):
+        self.source = EmailBaseModel(
+            document_type=self.document_type,
+            host='', username='', password='', store_body=True
+        )
+
+
+    def test_decode_email_base64_encoded_filename(self):
+        """
+        Test decoding of base64 encoded e-mail attachment filename.
+        """
+        self._create_email_source()
+        EmailBaseModel.process_message(
+            source=self.source, message_text=TEST_EMAIL_BASE64_FILENAME
+        )
+
+        self.assertEqual(
+            Document.objects.first().label, 'Ampelm\xe4nnchen.txt'
+        )
+
+    def test_decode_email_no_content_type(self):
+        self._create_email_source()
+        EmailBaseModel.process_message(
+            source=self.source, message_text=TEST_EMAIL_NO_CONTENT_TYPE
+        )
+        self.assertTrue(
+            TEST_EMAIL_NO_CONTENT_TYPE_STRING in Document.objects.first().open().read()
+        )
+
+    def test_decode_email_with_inline_image(self):
+        self._create_email_source()
+        EmailBaseModel.process_message(
+            source=self.source, message_text=TEST_EMAIL_INLINE_IMAGE
+        )
+        self.assertTrue(Document.objects.count(), 2)
+        self.assertQuerysetEqual(
+            ordered=False, qs=Document.objects.all(), values=(
+                '<Document: test-01.png>', '<Document: email_body.html>'
+            ),
+        )
+
+    def test_decode_email_with_attachment_and_inline_image(self):
+        self._create_email_source()
+        EmailBaseModel.process_message(
+            source=self.source, message_text=TEST_EMAIL_ATTACHMENT_AND_INLINE
+        )
+        self.assertTrue(Document.objects.count(), 2)
+        self.assertQuerysetEqual(
+            ordered=False, qs=Document.objects.all(), values=(
+                '<Document: test-01.png>', '<Document: email_body.html>',
+                '<Document: test-02.png>'
+            ),
+        )
diff --git a/requirements/base.txt b/requirements/base.txt
index dda95e2e90..432c454ce3 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -24,6 +24,7 @@ djangorestframework==3.7.7
 djangorestframework-recursive==0.1.2
 drf-yasg==1.5.0
 
+flanker==0.8.5
 flex==6.12.0
 furl==1.0.1
 fusepy==2.0.4
diff --git a/setup.py b/setup.py
index 567cc0201f..c2a9553ade 100644
--- a/setup.py
+++ b/setup.py
@@ -61,40 +61,41 @@ Pillow==5.0.0
 PyYAML==3.12
 celery==3.1.24
 cssmin==0.2.0
-django-activity-stream==0.6.3
+django-activity-stream==0.6.5
 django-autoadmin==1.1.1
 django-celery==3.2.1
 django-colorful==1.2
-django-compressor==2.1
-django-cors-headers==1.2.2
+django-compressor==2.2
+django-cors-headers==2.2.0
 django-downloadview==1.9
-django-formtools==2.0
+django-formtools==2.1
 django-pure-pagination==0.3.0
 django-mathfilters==0.4.0
-django-model-utils==2.6.1
-django-mptt>=0.8.7
-django-qsstats-magic==0.7.2
-django-rest-swagger==0.3.10
-django-stronghold==0.2.8
-django-suit==0.2.25
+django-model-utils==3.1.1
+django-mptt==0.9.0
+django-qsstats-magic==1.0.0
+django-stronghold==0.3.0
+django-suit==0.2.26
 django-widget-tweaks==1.4.1
 djangorestframework==3.7.7
 djangorestframework-recursive==0.1.2
 drf-yasg==1.5.0
+flanker==0.8.5
 flex==6.12.0
 furl==1.0.1
 fusepy==2.0.4
-graphviz==0.8
+graphviz==0.8.2
 mock==2.0.0
 pycountry==1.20
 PyPDF2==1.26.0
-pyocr==0.4.5
-python-dateutil==2.5.3
+pyocr==0.5.1
+python-dateutil==2.6.1
 python-gnupg==0.3.9
-python-magic==0.4.13
-pytz==2016.7
+python-magic==0.4.15
+pytz==2018.3
 requests==2.18.4
-sh==1.12.11
+sh==1.12.14
+swagger-spec-validator==2.1.0
 """.split()
 
 with open('README.rst') as f: