diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8456653..4af0dc6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 - Introduced `squelch_auto_margin` config option that allows configuring the auto squelch level
 - Removed `port` configuration option; `rtltcp_compat` takes the port number with the new connectors
 - Added support for new WSJT-X modes FST4 and FST4W (only available with WSJT-X 2.3)
+- Added support for demodulating M17 digital voice signals using m17-cxx-demod
 - New devices supported:
   - HPSDR devices (Hermes Lite 2)
   - BBRF103 / RX666 / RX888 devices supported by libsddc
diff --git a/csdr/csdr.py b/csdr/csdr.py
index d663b81..b95c10f 100644
--- a/csdr/csdr.py
+++ b/csdr/csdr.py
@@ -216,11 +216,11 @@ class dsp(object):
                 "csdr convert_f_s16"
             ]
         elif self.isDigitalVoice(which):
-            chain += ["csdr fmdemod_quadri_cf", "dc_block "]
+            chain += ["csdr fmdemod_quadri_cf"]
             chain += last_decimation_block
             # dsd modes
             if which in ["dstar", "nxdn"]:
-                chain += ["csdr limit_ff", "csdr convert_f_s16"]
+                chain += ["dc_block", "csdr limit_ff", "csdr convert_f_s16"]
                 if which == "dstar":
                     chain += ["dsd -fd -i - -o - -u {unvoiced_quality} -g -1 "]
                 elif which == "nxdn":
@@ -230,9 +230,18 @@ class dsp(object):
                     "CSDR_FIXED_BUFSIZE=32 csdr agc_s16 --max 30 --initial 3",
                     "sox -t raw -r 8000 -e signed-integer -b 16 -c 1 --buffer 32 - -t raw -r {output_rate} -e signed-integer -b 16 -c 1 - ",
                 ]
+            # m17
+            elif which == "m17":
+                chain += [
+                    "csdr limit_ff",
+                    "csdr convert_f_s16",
+                    "m17-demod",
+                    "CSDR_FIXED_BUFSIZE=32 csdr agc_s16 --max 30 --initial 3",
+                    "sox -t raw -r 8000 -e signed-integer -b 16 -c 1 --buffer 32 - -t raw -r {output_rate} -e signed-integer -b 16 -c 1 - ",
+                ]
             # digiham modes
             else:
-                chain += ["rrc_filter", "gfsk_demodulator"]
+                chain += ["dc_block", "rrc_filter", "gfsk_demodulator"]
                 if which == "dmr":
                     chain += [
                         "dmr_decoder --fifo {meta_pipe} --control-fifo {dmr_control_pipe}",
@@ -585,7 +594,7 @@ class dsp(object):
     def isDigitalVoice(self, demodulator=None):
         if demodulator is None:
             demodulator = self.get_demodulator()
-        return demodulator in ["dmr", "dstar", "nxdn", "ysf"]
+        return demodulator in ["dmr", "dstar", "nxdn", "ysf", "m17"]
 
     def isWsjtMode(self, demodulator=None):
         if demodulator is None:
diff --git a/debian/changelog b/debian/changelog
index c7dc727..b4f9544 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -5,6 +5,8 @@ openwebrx (0.21.0) UNRELEASED; urgency=low
     with the new connectors
   * Added support for new WSJT-X modes FST4 and FST4W (only available with
     WSJT-X 2.3)
+  * Added support for demodulating M17 digital voice signals using
+    m17-cxx-demod
   * New devices supported:
     - HPSDR devices (Hermes Lite 2) (`"type": "hpsdr"`)
     - BBRF103 / RX666 / RX888 devices supported by libsddc (`"type": "sddc"`)
diff --git a/docker/scripts/install-dependencies.sh b/docker/scripts/install-dependencies.sh
index 338201c..55a95e7 100755
--- a/docker/scripts/install-dependencies.sh
+++ b/docker/scripts/install-dependencies.sh
@@ -18,8 +18,8 @@ function cmakebuild() {
 
 cd /tmp
 
-STATIC_PACKAGES="sox libfftw3-bin python3 python3-setuptools netcat-openbsd libsndfile1 liblapack3 libusb-1.0-0 libqt5core5a libreadline7 libgfortran4 libgomp1 libasound2 libudev1 ca-certificates libqt5gui5 libqt5sql5 libqt5printsupport5 libpulse0 libfaad2 libopus0"
-BUILD_PACKAGES="wget git libsndfile1-dev libfftw3-dev cmake make gcc g++ liblapack-dev texinfo gfortran libusb-1.0-0-dev qtbase5-dev qtmultimedia5-dev qttools5-dev libqt5serialport5-dev qttools5-dev-tools asciidoctor asciidoc libasound2-dev libudev-dev libhamlib-dev patch xsltproc qt5-default libfaad-dev libopus-dev"
+STATIC_PACKAGES="sox libfftw3-bin python3 python3-setuptools netcat-openbsd libsndfile1 liblapack3 libusb-1.0-0 libqt5core5a libreadline7 libgfortran4 libgomp1 libasound2 libudev1 ca-certificates libqt5gui5 libqt5sql5 libqt5printsupport5 libpulse0 libfaad2 libopus0 libboost-program-options1.67.0"
+BUILD_PACKAGES="wget git libsndfile1-dev libfftw3-dev cmake make gcc g++ liblapack-dev texinfo gfortran libusb-1.0-0-dev qtbase5-dev qtmultimedia5-dev qttools5-dev libqt5serialport5-dev qttools5-dev-tools asciidoctor asciidoc libasound2-dev libudev-dev libhamlib-dev patch xsltproc qt5-default libfaad-dev libopus-dev libgtest-dev libboost-dev libboost-program-options-dev"
 apt-get update
 apt-get -y install auto-apt-proxy
 apt-get -y install --no-install-recommends $STATIC_PACKAGES $BUILD_PACKAGES
@@ -110,6 +110,10 @@ popd
 rm -rf dream
 rm dream-2.1.1-svn808.tar.gz
 
+git clone https://github.com/mobilinkd/m17-cxx-demod.git
+# latest master as of 2020-12-27 (new sync words)
+cmakebuild m17-cxx-demod 2b84657676efb3b07b33de3ab3d0a6218e9d88b5
+
 git clone https://github.com/hessu/aprs-symbols /usr/share/aprs-symbols
 pushd /usr/share/aprs-symbols
 git checkout 5c2abe2658ee4d2563f3c73b90c6f59124839802
diff --git a/owrx/feature.py b/owrx/feature.py
index 39c6c20..fbdb425 100644
--- a/owrx/feature.py
+++ b/owrx/feature.py
@@ -75,6 +75,7 @@ class FeatureDetector(object):
         "digital_voice_digiham": ["digiham", "sox"],
         "digital_voice_dsd": ["dsd", "sox", "digiham"],
         "digital_voice_freedv": ["freedv_rx", "sox"],
+        "digital_voice_m17": ["m17_demod", "sox"],
         "wsjt-x": ["wsjtx", "sox"],
         "packet": ["direwolf", "sox"],
         "pocsag": ["digiham", "sox"],
@@ -150,7 +151,7 @@ class FeatureDetector(object):
         # prevent X11 programs from opening windows if called from a GUI shell
         env.pop("DISPLAY", None)
         try:
-            process = subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, cwd=tmp_dir, env=env)
+            process = subprocess.Popen(cmd, stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, cwd=tmp_dir, env=env)
             rc = process.wait()
             if expected_result is None:
                 return rc != 32512
@@ -419,6 +420,14 @@ class FeatureDetector(object):
         """
         return self.command_is_runnable("dsd")
 
+    def has_m17_demod(self):
+        """
+        The `m17-demod` tool is used to demodulate M17 digital voice signals.
+
+        You can find more information [here](https://github.com/mobilinkd/m17-cxx-demod)
+        """
+        return self.command_is_runnable("m17-demod")
+
     def has_sox(self):
         """
         The sox audio library is used to convert between the typical 8 kHz audio sampling rate used by digital modes and
diff --git a/owrx/modes.py b/owrx/modes.py
index 0d1561f..8b642e1 100644
--- a/owrx/modes.py
+++ b/owrx/modes.py
@@ -63,6 +63,7 @@ class Modes(object):
         AnalogMode("dstar", "D-Star", bandpass=Bandpass(-3250, 3250), requirements=["digital_voice_dsd"], squelch=False),
         AnalogMode("nxdn", "NXDN", bandpass=Bandpass(-3250, 3250), requirements=["digital_voice_dsd"], squelch=False),
         AnalogMode("ysf", "YSF", bandpass=Bandpass(-4000, 4000), requirements=["digital_voice_digiham"], squelch=False),
+        AnalogMode("m17", "M17", bandpass=Bandpass(-4000, 4000), requirements=["digital_voice_m17"], squelch=False),
         AnalogMode("freedv", "FreeDV", bandpass=Bandpass(300, 3000), requirements=["digital_voice_freedv"], squelch=False),
         AnalogMode("drm", "DRM", bandpass=Bandpass(-5000, 5000), requirements=["drm"], squelch=False),
         DigitalMode("bpsk31", "BPSK31", underlying=["usb"]),
diff --git a/owrx/source/sdrplay.py b/owrx/source/sdrplay.py
index da2398a..5fb2f4c 100644
--- a/owrx/source/sdrplay.py
+++ b/owrx/source/sdrplay.py
@@ -10,6 +10,7 @@ class SdrplaySource(SoapyConnectorSource):
                 "rf_notch": "rfnotch_ctrl",
                 "dab_notch": "dabnotch_ctrl",
                 "if_mode": "if_mode",
+                "external_reference": "extref_ctrl",
             }
         )
         return mappings