diff --git a/README.rst b/README.rst
index 10ad4d3c..46880c9d 100644
--- a/README.rst
+++ b/README.rst
@@ -50,6 +50,7 @@ To get started with Mopidy, check out
 `the installation docs <http://docs.mopidy.com/en/latest/installation/>`_.
 
 - `Documentation <http://docs.mopidy.com/>`_
+- `Discuss <https://discuss.mopidy.com/>`_
 - `Source code <https://github.com/mopidy/mopidy>`_
 - `Issue tracker <https://github.com/mopidy/mopidy/issues>`_
 - `Development branch tarball <https://github.com/mopidy/mopidy/archive/develop.tar.gz#egg=mopidy-dev>`_
diff --git a/docs/api/concepts.rst b/docs/api/concepts.rst
index 68718935..d127561b 100644
--- a/docs/api/concepts.rst
+++ b/docs/api/concepts.rst
@@ -6,14 +6,15 @@ Architecture and concepts
 
 The overall architecture of Mopidy is organized around multiple frontends and
 backends. The frontends use the core API. The core actor makes multiple backends
-work as one. The backends connect to various music sources. Both the core actor
-and the backends use the audio actor to play audio and control audio volume.
+work as one. The backends connect to various music sources. The core actor use
+the mixer actor to control volume, while the backends use the audio actor to
+play audio.
 
 .. digraph:: overall_architecture
 
     "Multiple frontends" -> Core
     Core -> "Multiple backends"
-    Core -> Audio
+    Core -> Mixer
     "Multiple backends" -> Audio
 
 
@@ -93,7 +94,15 @@ Audio
 =====
 
 The audio actor is a thin wrapper around the parts of the GStreamer library we
-use. In addition to playback, it's responsible for volume control through both
-GStreamer's own volume mixers, and mixers we've created ourselves. If you
-implement an advanced backend, you may need to implement your own playback
-provider using the :ref:`audio-api`.
+use. If you implement an advanced backend, you may need to implement your own
+playback provider using the :ref:`audio-api`.
+
+
+Mixer
+=====
+
+The mixer actor is responsible for volume control and muting. The default
+mixer use the audio actor to control volume in software. The alternative
+implementations are typically independent of the audio actor, but instead use
+some third party Python library or a serial interface to control other forms
+of volume controls.
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 8948fe6e..7eefd533 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -13,18 +13,42 @@ v0.20.0 (UNRELEASED)
 - Add cover URL to all scanned files with MusicBrainz album IDs. (Fixes:
   :issue:`697`, PR: :issue:`802`)
 
+**MPD frontend**
 
-v0.19.4 (UNRELEASED)
+- In stored playlist names, replace "/", which are illegal, with "|" instead of
+  a whitespace. Pipes are more similar to forward slash.
+
+
+v0.19.4 (2014-09-01)
 ====================
 
 Bug fix release.
 
+- Configuration: :option:`mopidy --config` now supports directories.
+
+- Logging: Fix that some loggers would be disabled if
+  :confval:`logging/config_file` was set. (Fixes: :issue:`740`)
+
+- Quit process with exit code 1 when stopping because of a backend, frontend,
+  or mixer initialization error.
+
+- Backend API: Update :meth:`mopidy.backend.LibraryProvider.browse` signature
+  and docs to match how the core use the backend's browse method. (Fixes:
+  :issue:`833`)
+
+- Local library API: Add :attr:`mopidy.local.Library.ROOT_DIRECTORY_URI`
+  constant for use by implementors of :meth:`mopidy.local.Library.browse`.
+  (Related to: :issue:`833`)
+
+- HTTP frontend: Guard against double close of WebSocket, which causes an
+  :exc:`AttributeError` on Tornado < 3.2.
+
 - MPD frontend: Make the ``list`` command return albums when sending 3
   arguments. This was incorrectly returning artists after the MPD command
   changes in 0.19.0. (Fixes: :issue:`817`)
 
-- Logging: Fix that some loggers would be disabled if
-  :confval:`logging/config_file` was set. (Fixes: :issue:`740`)
+- MPD frontend: Fix a race condition where two threads could try to free the
+  same data simultaneously. (Fixes: :issue:`781`)
 
 
 v0.19.3 (2014-08-03)
diff --git a/docs/command.rst b/docs/command.rst
index 79ca3ed0..881fb513 100644
--- a/docs/command.rst
+++ b/docs/command.rst
@@ -50,11 +50,12 @@ Options
     Save debug log to the file specified in the :confval:`logging/debug_file`
     config value, typically ``./mopidy.log``.
 
-.. cmdoption:: --config <file>
+.. cmdoption:: --config <file|directory>
 
-    Specify config file to use. To use multiple config files, separate them
-    with a colon. The later files override the earlier ones if there's a
-    conflict.
+    Specify config files and directories to use. To use multiple config files
+    or directories, separate them with a colon. The later files override the
+    earlier ones if there's a conflict. When specifying a directory, all files
+    ending in .conf in the directory are used.
 
 .. cmdoption:: --option <option>, -o <option>
 
diff --git a/docs/conf.py b/docs/conf.py
index 52e84e06..1eb6dd33 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -52,6 +52,7 @@ MOCK_MODULES = [
     'glib',
     'gobject',
     'gst',
+    'gst.pbutils',
     'pygst',
     'pykka',
     'pykka.actor',
diff --git a/docs/index.rst b/docs/index.rst
index 71e8dee7..bd324af7 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -56,15 +56,20 @@ To get started with Mopidy, start by reading :ref:`installation`.
 
 **Getting help**
 
-If you get stuck, we usually hang around at ``#mopidy`` at `irc.freenode.net
-<http://freenode.net/>`_ (with `searchable logs
-<https://botbot.me/freenode/mopidy/>`_) and also have a `mailing list at Google
-Groups <https://groups.google.com/forum/?fromgroups=#!forum/mopidy>`_. If you
-stumble into a bug or got a feature request, please create an issue in the
-`issue tracker <https://github.com/mopidy/mopidy/issues>`_. The `source code
-<https://github.com/mopidy/mopidy>`_ may also be of help. If you want to stay
-up to date on Mopidy developments, you can follow `@mopidy
-<https://twitter.com/mopidy/>`_ on Twitter.
+If you get stuck, you can get help at the `Mopidy discussion forum
+<https://discuss.mopidy.com/>`_. We also hang around at IRC on the ``#mopidy``
+channel at `irc.freenode.net <http://freenode.net/>`_. The IRC channel has
+`public searchable logs <https://botbot.me/freenode/mopidy/>`_.
+
+If you stumble into a bug or have a feature request, please create an issue in
+the `issue tracker <https://github.com/mopidy/mopidy/issues>`_. If you're
+unsure if its a bug or not, ask for help in the forum or at IRC first. The
+`source code <https://github.com/mopidy/mopidy>`_ may also be of help.
+
+If you want to stay up to date on Mopidy developments, you can follow `@mopidy
+<https://twitter.com/mopidy/>`_ on Twitter. There's also a `mailing list
+<https://groups.google.com/forum/?fromgroups=#!forum/mopidy>`_ used for
+announcements related to Mopidy and Mopidy extensions.
 
 
 Usage
@@ -118,6 +123,7 @@ About
     :maxdepth: 1
 
     authors
+    sponsors
     changelog
     versioning
 
diff --git a/docs/sponsors.rst b/docs/sponsors.rst
new file mode 100644
index 00000000..67aef554
--- /dev/null
+++ b/docs/sponsors.rst
@@ -0,0 +1,38 @@
+.. _sponsors:
+
+********
+Sponsors
+********
+
+The Mopidy project would like to thank the following sponsors for supporting
+the project.
+
+
+Rackspace
+=========
+
+`Rackspace <http://www.rackspace.com/>`_ lets Mopidy use their hosting services
+for free. We use their services for the following sites:
+
+- Hosting of the APT package repository at https://apt.mopidy.com.
+
+- Hosting of the Discourse forum at https://discuss.mopidy.com.
+
+- Mailgun for sending emails from the Discourse forum.
+
+- Hosting of the Jenkins CI server at https://ci.mopidy.com.
+
+- Hosting of a Linux worker for https://ci.mopidy.com.
+
+- Hosting of a Windows worker for https://ci.mopidy.com.
+
+- CDN hosting at http://dl.mopidy.com, which is used to distribute Pi Musicbox
+  images.
+
+
+GlobalSign
+==========
+
+`GlobalSign <https://www.globalsign.com/>`_ provides Mopidy with a free
+wildcard SSL certificate for mopidy.com, which we use to secure access to all
+our web sites.
diff --git a/mopidy/__init__.py b/mopidy/__init__.py
index 47e36e06..7b55f20a 100644
--- a/mopidy/__init__.py
+++ b/mopidy/__init__.py
@@ -21,4 +21,4 @@ if (isinstance(pykka.__version__, basestring)
 warnings.filterwarnings('ignore', 'could not open display')
 
 
-__version__ = '0.19.3'
+__version__ = '0.19.4'
diff --git a/mopidy/backend/__init__.py b/mopidy/backend/__init__.py
index 845eac11..712bfafe 100644
--- a/mopidy/backend/__init__.py
+++ b/mopidy/backend/__init__.py
@@ -81,12 +81,12 @@ class LibraryProvider(object):
     def __init__(self, backend):
         self.backend = backend
 
-    def browse(self, path):
+    def browse(self, uri):
         """
         See :meth:`mopidy.core.LibraryController.browse`.
 
         If you implement this method, make sure to also set
-        :attr:`root_directory_name`.
+        :attr:`root_directory`.
 
         *MAY be implemented by subclass.*
         """
diff --git a/mopidy/commands.py b/mopidy/commands.py
index f7c71d4e..237ec86b 100644
--- a/mopidy/commands.py
+++ b/mopidy/commands.py
@@ -265,6 +265,7 @@ class RootCommand(Command):
         backend_classes = args.registry['backend']
         frontend_classes = args.registry['frontend']
 
+        exit_status_code = 0
         try:
             mixer = self.start_mixer(config, mixer_class)
             audio = self.start_audio(config, mixer)
@@ -276,8 +277,11 @@ class RootCommand(Command):
                 exceptions.FrontendError,
                 exceptions.MixerError):
             logger.info('Initialization error. Exiting...')
+            exit_status_code = 1
         except KeyboardInterrupt:
             logger.info('Interrupted. Exiting...')
+        except Exception:
+            logger.exception('Uncaught exception')
         finally:
             loop.quit()
             self.stop_frontends(frontend_classes)
@@ -286,6 +290,7 @@ class RootCommand(Command):
             self.stop_audio()
             self.stop_mixer(mixer_class)
             process.stop_remaining_actors()
+            return exit_status_code
 
     def get_mixer_class(self, config, mixer_classes):
         logger.debug(
diff --git a/mopidy/config/__init__.py b/mopidy/config/__init__.py
index ed8446dd..61971875 100644
--- a/mopidy/config/__init__.py
+++ b/mopidy/config/__init__.py
@@ -114,27 +114,14 @@ def _load(files, defaults, overrides):
 
     # Load config from a series of config files
     files = [path.expand_path(f) for f in files]
-    for filename in files:
-        if not os.path.exists(filename):
-            logger.debug(
-                'Loading config from %s failed; it does not exist', filename)
-            continue
-
-        try:
-            logger.info('Loading config from %s', filename)
-            with io.open(filename, 'rb') as filehandle:
-                parser.readfp(filehandle)
-        except configparser.MissingSectionHeaderError as e:
-            logger.warning('%s does not have a config section, not loaded.',
-                           filename)
-        except configparser.ParsingError as e:
-            linenos = ', '.join(str(lineno) for lineno, line in e.errors)
-            logger.warning(
-                '%s has errors, line %s has been ignored.', filename, linenos)
-        except IOError:
-            # TODO: if this is the initial load of logging config we might not
-            # have a logger at this point, we might want to handle this better.
-            logger.debug('Config file %s not found; skipping', filename)
+    for name in files:
+        if os.path.isdir(name):
+            for filename in os.listdir(name):
+                filename = os.path.join(name, filename)
+                if os.path.isfile(filename) and filename.endswith('.conf'):
+                    _load_file(parser, filename)
+        else:
+            _load_file(parser, name)
 
     # If there have been parse errors there is a python bug that causes the
     # values to be lists, this little trick coerces these into strings.
@@ -151,6 +138,29 @@ def _load(files, defaults, overrides):
     return raw_config
 
 
+def _load_file(parser, filename):
+    if not os.path.exists(filename):
+        logger.debug(
+            'Loading config from %s failed; it does not exist', filename)
+        return
+
+    try:
+        logger.info('Loading config from %s', filename)
+        with io.open(filename, 'rb') as filehandle:
+            parser.readfp(filehandle)
+    except configparser.MissingSectionHeaderError as e:
+        logger.warning('%s does not have a config section, not loaded.',
+                       filename)
+    except configparser.ParsingError as e:
+        linenos = ', '.join(str(lineno) for lineno, line in e.errors)
+        logger.warning(
+            '%s has errors, line %s has been ignored.', filename, linenos)
+    except IOError:
+        # TODO: if this is the initial load of logging config we might not
+        # have a logger at this point, we might want to handle this better.
+        logger.debug('Config file %s not found; skipping', filename)
+
+
 def _validate(raw_config, schemas):
     # Get validated config
     config = {}
diff --git a/mopidy/http/handlers.py b/mopidy/http/handlers.py
index e212c77d..3ef10c3b 100644
--- a/mopidy/http/handlers.py
+++ b/mopidy/http/handlers.py
@@ -110,7 +110,10 @@ class WebSocketHandler(tornado.websocket.WebSocketHandler):
                     self.request.remote_ip, response)
         except Exception as e:
             logger.error('WebSocket request error: %s', e)
-            self.close()
+            if self.ws_connection:
+                # Tornado 3.2+ checks if self.ws_connection is None before
+                # using it, but not older versions.
+                self.close()
 
     def check_origin(self, origin):
         # Allow cross-origin WebSocket connections, like Tornado before 4.0
diff --git a/mopidy/local/__init__.py b/mopidy/local/__init__.py
index 8b4a8b1f..104c43af 100644
--- a/mopidy/local/__init__.py
+++ b/mopidy/local/__init__.py
@@ -58,17 +58,28 @@ class Library(object):
     :param config: Config dictionary
     """
 
+    ROOT_DIRECTORY_URI = 'local:directory'
+    """
+    URI of the local backend's root directory.
+
+    This constant should be used by libraries implementing the
+    :meth:`Library.browse` method.
+    """
+
     #: Name of the local library implementation, must be overriden.
     name = None
 
     def __init__(self, config):
         self._config = config
 
-    def browse(self, path):
+    def browse(self, uri):
         """
-        Browse directories and tracks at the given path.
+        Browse directories and tracks at the given URI.
 
-        :param string path: path to browse or None for root.
+        The URI for the root directory is a constant available at
+        :attr:`Library.ROOT_DIRECTORY_URI`.
+
+        :param string path: URI to browse.
         :rtype: List of :class:`~mopidy.models.Ref` tracks and directories.
         """
         raise NotImplementedError
diff --git a/mopidy/local/json.py b/mopidy/local/json.py
index 927f8898..5ae04592 100644
--- a/mopidy/local/json.py
+++ b/mopidy/local/json.py
@@ -61,8 +61,8 @@ class _BrowseCache(object):
     splitpath_re = re.compile(r'([^/]+)')
 
     def __init__(self, uris):
-        # TODO: local.ROOT_DIRECTORY_URI
-        self._cache = {'local:directory': collections.OrderedDict()}
+        self._cache = {
+            local.Library.ROOT_DIRECTORY_URI: collections.OrderedDict()}
 
         for track_uri in uris:
             path = translator.local_track_uri_to_path(track_uri, b'/')
@@ -97,10 +97,11 @@ class _BrowseCache(object):
             else:
                 # Loop completed, so final child needs to be added to root.
                 if child:
-                    self._cache['local:directory'][child.uri] = child
+                    self._cache[
+                        local.Library.ROOT_DIRECTORY_URI][child.uri] = child
                 # If no parent was set we belong in the root.
                 if not parent_uri:
-                    parent_uri = 'local:directory'
+                    parent_uri = local.Library.ROOT_DIRECTORY_URI
 
             self._cache[parent_uri][track_uri] = track_ref
 
diff --git a/mopidy/local/library.py b/mopidy/local/library.py
index a626f566..a4645084 100644
--- a/mopidy/local/library.py
+++ b/mopidy/local/library.py
@@ -2,7 +2,7 @@ from __future__ import unicode_literals
 
 import logging
 
-from mopidy import backend, models
+from mopidy import backend, local, models
 
 logger = logging.getLogger(__name__)
 
@@ -10,18 +10,18 @@ logger = logging.getLogger(__name__)
 class LocalLibraryProvider(backend.LibraryProvider):
     """Proxy library that delegates work to our active local library."""
 
-    root_directory = models.Ref.directory(uri=b'local:directory',
-                                          name='Local media')
+    root_directory = models.Ref.directory(
+        uri=local.Library.ROOT_DIRECTORY_URI, name='Local media')
 
     def __init__(self, backend, library):
         super(LocalLibraryProvider, self).__init__(backend)
         self._library = library
         self.refresh()
 
-    def browse(self, path):
+    def browse(self, uri):
         if not self._library:
             return []
-        return self._library.browse(path)
+        return self._library.browse(uri)
 
     def refresh(self, uri=None):
         if not self._library:
diff --git a/mopidy/mpd/dispatcher.py b/mopidy/mpd/dispatcher.py
index 84550698..9c2f3471 100644
--- a/mopidy/mpd/dispatcher.py
+++ b/mopidy/mpd/dispatcher.py
@@ -269,7 +269,7 @@ class MpdContext(object):
                 if not playlist.name:
                     continue
                 # TODO: add scheme to name perhaps 'foo (spotify)' etc.
-                name = self._invalid_playlist_chars.sub(' ', playlist.name)
+                name = self._invalid_playlist_chars.sub('|', playlist.name)
                 self.insert_name_uri_mapping(name, playlist.uri)
 
     def lookup_playlist_from_name(self, name):
diff --git a/mopidy/utils/network.py b/mopidy/utils/network.py
index 11469b47..4ea25026 100644
--- a/mopidy/utils/network.py
+++ b/mopidy/utils/network.py
@@ -268,8 +268,8 @@ class Connection(object):
             return True
 
         if not data:
-            self.actor_ref.tell({'close': True})
             self.disable_recv()
+            self.actor_ref.tell({'close': True})
             return True
 
         try:
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index 52035825..da0e5192 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -60,6 +60,18 @@ class LoadConfigTest(unittest.TestCase):
         result = config._load([file1, file2], [], [])
         self.assertEqual(expected, result)
 
+    def test_load_directory(self):
+        directory = path_to_data_dir('conf1.d')
+        expected = {'foo': {'bar': 'baz'}, 'foo2': {'bar': 'baz'}}
+        result = config._load([directory], [], [])
+        self.assertEqual(expected, result)
+
+    def test_load_directory_only_conf_files(self):
+        directory = path_to_data_dir('conf2.d')
+        expected = {'foo': {'bar': 'baz'}}
+        result = config._load([directory], [], [])
+        self.assertEqual(expected, result)
+
     def test_load_file_with_utf8(self):
         expected = {'foo': {'bar': 'æøå'.encode('utf-8')}}
         result = config._load([path_to_data_dir('file3.conf')], [], [])
diff --git a/tests/data/conf1.d/file1.conf b/tests/data/conf1.d/file1.conf
new file mode 100644
index 00000000..e6396bff
--- /dev/null
+++ b/tests/data/conf1.d/file1.conf
@@ -0,0 +1,2 @@
+[foo]
+bar = baz
diff --git a/tests/data/conf1.d/file2.conf b/tests/data/conf1.d/file2.conf
new file mode 100644
index 00000000..ef189703
--- /dev/null
+++ b/tests/data/conf1.d/file2.conf
@@ -0,0 +1,2 @@
+[foo2]
+bar = baz
diff --git a/tests/data/conf2.d/file1.conf b/tests/data/conf2.d/file1.conf
new file mode 100644
index 00000000..e6396bff
--- /dev/null
+++ b/tests/data/conf2.d/file1.conf
@@ -0,0 +1,2 @@
+[foo]
+bar = baz
diff --git a/tests/data/conf2.d/file2.conf.disabled b/tests/data/conf2.d/file2.conf.disabled
new file mode 100644
index 00000000..ef189703
--- /dev/null
+++ b/tests/data/conf2.d/file2.conf.disabled
@@ -0,0 +1,2 @@
+[foo2]
+bar = baz
diff --git a/tests/mpd/protocol/test_stored_playlists.py b/tests/mpd/protocol/test_stored_playlists.py
index 56011435..4dc7dbbb 100644
--- a/tests/mpd/protocol/test_stored_playlists.py
+++ b/tests/mpd/protocol/test_stored_playlists.py
@@ -121,12 +121,12 @@ class PlaylistsHandlerTest(protocol.BaseTestCase):
         self.assertNotInResponse('playlist: a\r')
         self.assertInResponse('OK')
 
-    def test_listplaylists_replaces_forward_slash_with_space(self):
+    def test_listplaylists_replaces_forward_slash_with_pipe(self):
         self.backend.playlists.playlists = [
-            Playlist(name='a/', uri='dummy:')]
+            Playlist(name='a/b', uri='dummy:')]
         self.sendRequest('listplaylists')
-        self.assertInResponse('playlist: a ')
-        self.assertNotInResponse('playlist: a/')
+        self.assertInResponse('playlist: a|b')
+        self.assertNotInResponse('playlist: a/b')
         self.assertInResponse('OK')
 
     def test_load_appends_to_tracklist(self):
diff --git a/tests/test_version.py b/tests/test_version.py
index 0431beae..96063a1b 100644
--- a/tests/test_version.py
+++ b/tests/test_version.py
@@ -49,5 +49,6 @@ class VersionTest(unittest.TestCase):
         self.assertLess(SV('0.18.3'), SV('0.19.0'))
         self.assertLess(SV('0.19.0'), SV('0.19.1'))
         self.assertLess(SV('0.19.1'), SV('0.19.2'))
-        self.assertLess(SV('0.19.2'), SV(__version__))
-        self.assertLess(SV(__version__), SV('0.19.4'))
+        self.assertLess(SV('0.19.2'), SV('0.19.3'))
+        self.assertLess(SV('0.19.3'), SV(__version__))
+        self.assertLess(SV(__version__), SV('0.19.5'))
diff --git a/tests/utils/network/test_connection.py b/tests/utils/network/test_connection.py
index 7a25643f..c3200689 100644
--- a/tests/utils/network/test_connection.py
+++ b/tests/utils/network/test_connection.py
@@ -7,7 +7,7 @@ import unittest
 
 import gobject
 
-from mock import Mock, patch, sentinel
+from mock import Mock, call, patch, sentinel
 
 import pykka
 
@@ -418,8 +418,11 @@ class ConnectionTest(unittest.TestCase):
 
         self.assertTrue(network.Connection.recv_callback(
             self.mock, sentinel.fd, gobject.IO_IN))
-        self.mock.actor_ref.tell.assert_called_once_with({'close': True})
-        self.mock.disable_recv.assert_called_once_with()
+        self.assertEqual(self.mock.mock_calls, [
+            call.sock.recv(any_int),
+            call.disable_recv(),
+            call.actor_ref.tell({'close': True}),
+        ])
 
     def test_recv_callback_recoverable_error(self):
         self.mock.sock = Mock(spec=socket.SocketType)