diff --git a/Dockerfile b/Dockerfile
index fb015cb..495699e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,4 @@
 FROM    php:apache
-COPY    backend-php/ /var/www/html/
-COPY    frontend/ /var/www/html/
-COPY    docker/start.sh .
 
 RUN     apt-get update && \
         apt-get install -y memcached libmemcached-dev zlib1g-dev libldap2-dev && \
@@ -12,7 +9,11 @@ RUN     apt-get update && \
 
 EXPOSE  80/tcp
 VOLUME  /etc/hauk
-
 STOPSIGNAL SIGINT
+
+COPY    docker/start.sh .
 RUN     chmod +x ./start.sh
+COPY    backend-php/ /var/www/html/
+COPY    frontend/ /var/www/html/
+
 CMD     ["./start.sh"]
diff --git a/android/app/src/main/java/info/varden/hauk/Constants.java b/android/app/src/main/java/info/varden/hauk/Constants.java
index e75524b..401e900 100644
--- a/android/app/src/main/java/info/varden/hauk/Constants.java
+++ b/android/app/src/main/java/info/varden/hauk/Constants.java
@@ -123,6 +123,7 @@ public enum Constants {
     public static final String PACKET_PARAM_SPEED = "spd";
     public static final String PACKET_PARAM_TIMESTAMP = "time";
     public static final String PACKET_PARAM_USERNAME = "usr";
+    public static final String PACKET_PARAM_ALTITUDE = "alt";
 
     // Packet OK response header. All valid packets start with this line.
     public static final String PACKET_RESPONSE_OK = "OK";
diff --git a/android/app/src/main/java/info/varden/hauk/http/LocationUpdatePacket.java b/android/app/src/main/java/info/varden/hauk/http/LocationUpdatePacket.java
index 4c571fa..21a86f7 100644
--- a/android/app/src/main/java/info/varden/hauk/http/LocationUpdatePacket.java
+++ b/android/app/src/main/java/info/varden/hauk/http/LocationUpdatePacket.java
@@ -5,9 +5,15 @@
 import android.util.Base64;
 
 import java.nio.charset.StandardCharsets;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.security.spec.InvalidKeySpecException;
 
+import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
 
 import info.varden.hauk.Constants;
 import info.varden.hauk.R;
@@ -48,36 +54,17 @@ protected LocationUpdatePacket(Context ctx, Session session, Location location,
         super(ctx, session.getServerURL(), session.getConnectionParameters(), Constants.URL_PATH_POST_LOCATION);
         setParameter(Constants.PACKET_PARAM_SESSION_ID, session.getID());
 
-        if (session.getDerivableE2EKey() == null) {
-            // If not using end-to-end encryption, send parameters in plain text.
-            setParameter(Constants.PACKET_PARAM_LATITUDE, String.valueOf(location.getLatitude()));
-            setParameter(Constants.PACKET_PARAM_LONGITUDE, String.valueOf(location.getLongitude()));
-            setParameter(Constants.PACKET_PARAM_PROVIDER_ACCURACY, String.valueOf(accuracy.getMode()));
-            setParameter(Constants.PACKET_PARAM_TIMESTAMP, String.valueOf(System.currentTimeMillis() / (double) TimeUtils.MILLIS_PER_SECOND));
+        Cipher cipher = initCipher(session);
 
-            // Not all devices provide these parameters:
-            if (location.hasSpeed()) setParameter(Constants.PACKET_PARAM_SPEED, String.valueOf(location.getSpeed()));
-            if (location.hasAccuracy()) setParameter(Constants.PACKET_PARAM_ACCURACY, String.valueOf(location.getAccuracy()));
-        } else {
-            // We're using end-to-end encryption - generate an IV and encrypt all parameters.
-            try {
-                Cipher cipher = Cipher.getInstance(Constants.E2E_TRANSFORMATION);
-                cipher.init(Cipher.ENCRYPT_MODE, session.getDerivableE2EKey().deriveSpec(), new SecureRandom());
-                byte[] iv = cipher.getIV();
-                setParameter(Constants.PACKET_PARAM_INIT_VECTOR, Base64.encodeToString(iv, Base64.DEFAULT));
+        encryptAndSetParameter(Constants.PACKET_PARAM_LATITUDE, location.getLatitude(), cipher);
+        encryptAndSetParameter(Constants.PACKET_PARAM_LONGITUDE, location.getLongitude(), cipher);
+        encryptAndSetParameter(Constants.PACKET_PARAM_PROVIDER_ACCURACY, accuracy.getMode(), cipher);
+        encryptAndSetParameter(Constants.PACKET_PARAM_TIMESTAMP, System.currentTimeMillis() / (double) TimeUtils.MILLIS_PER_SECOND, cipher);
 
-                setParameter(Constants.PACKET_PARAM_LATITUDE, Base64.encodeToString(cipher.doFinal(String.valueOf(location.getLatitude()).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-                setParameter(Constants.PACKET_PARAM_LONGITUDE, Base64.encodeToString(cipher.doFinal(String.valueOf(location.getLongitude()).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-                setParameter(Constants.PACKET_PARAM_PROVIDER_ACCURACY, Base64.encodeToString(cipher.doFinal(String.valueOf(accuracy.getMode()).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-                setParameter(Constants.PACKET_PARAM_TIMESTAMP, Base64.encodeToString(cipher.doFinal(String.valueOf(System.currentTimeMillis() / (double) TimeUtils.MILLIS_PER_SECOND).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-
-                // Not all devices provide these parameters:
-                if (location.hasSpeed()) setParameter(Constants.PACKET_PARAM_SPEED, Base64.encodeToString(cipher.doFinal(String.valueOf(location.getSpeed()).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-                if (location.hasAccuracy()) setParameter(Constants.PACKET_PARAM_ACCURACY, Base64.encodeToString(cipher.doFinal(String.valueOf(location.getAccuracy()).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
-            } catch (Exception e) {
-                Log.e("Error was thrown when encrypting location data", e); //NON-NLS
-            }
-        }
+        // Not all devices provide these parameters:
+        if (location.hasSpeed()) encryptAndSetParameter(Constants.PACKET_PARAM_SPEED, location.getSpeed(), cipher);
+        if (location.hasAccuracy()) encryptAndSetParameter(Constants.PACKET_PARAM_ACCURACY, location.getAccuracy(), cipher);
+        if (location.hasAltitude()) encryptAndSetParameter(Constants.PACKET_PARAM_ALTITUDE, location.getAltitude(), cipher);
     }
 
     @SuppressWarnings("DesignForExtension")
@@ -113,4 +100,33 @@ protected void onSuccess(String[] data, Version backendVersion) throws ServerExc
             throw new ServerException(err.toString());
         }
     }
+
+    private Cipher initCipher(Session session) {
+        Cipher cipher = null;
+        if (session.getDerivableE2EKey() != null) {
+            try {
+                cipher = Cipher.getInstance(Constants.E2E_TRANSFORMATION);
+                cipher.init(Cipher.ENCRYPT_MODE, session.getDerivableE2EKey().deriveSpec(), new SecureRandom());
+                byte[] iv = cipher.getIV();
+                setParameter(Constants.PACKET_PARAM_INIT_VECTOR, Base64.encodeToString(iv, Base64.DEFAULT));
+            } catch (NoSuchAlgorithmException | InvalidKeyException | InvalidKeySpecException | NoSuchPaddingException exception) {
+                Log.e("Error was thrown while initializing E2E encryption", exception); //NON-NLS
+            }
+        }
+        return cipher;
+    }
+
+    private <V> void encryptAndSetParameter(String key, V value, Cipher cipher) {
+        if (cipher != null) {
+            // We're using end-to-end encryption - generate an IV and encrypt all parameters.
+            try {
+                setParameter(key, Base64.encodeToString(cipher.doFinal(String.valueOf(value).getBytes(StandardCharsets.UTF_8)), Base64.DEFAULT));
+            } catch (BadPaddingException | IllegalBlockSizeException exception) {
+                Log.e("Error was thrown while encrypting location data", exception); //NON-NLS
+            }
+        } else {
+            // If not using end-to-end encryption, send parameters in plain text.
+            setParameter(key, String.valueOf(value));
+        }
+    }
 }
diff --git a/backend-php/api/post.php b/backend-php/api/post.php
index 05048c1..562e6e9 100644
--- a/backend-php/api/post.php
+++ b/backend-php/api/post.php
@@ -21,45 +21,37 @@
 $session = new Client($memcache, $sid);
 if (!$session->exists()) die($LANG['session_expired']."\n");
 
-if (!$session->isEncrypted()) {
-    // Perform input validation.
-    $lat = floatval($_POST["lat"]);
-    $lon = floatval($_POST["lon"]);
-    $time = floatval($_POST["time"]);
-    if ($lat < -90 || $lat > 90 || $lon < -180 || $lon > 180) die($LANG['location_invalid']."\n");
-
-    // Not all devices report speed and accuracy, but if available, report them
-    // too.
-    $speed = isset($_POST["spd"]) ? floatval($_POST["spd"]) : null;
-    $accuracy = isset($_POST["acc"]) ? floatval($_POST["acc"]) : null;
-    $provider = isset($_POST["prv"]) && $_POST["prv"] == "1" ? 1 : 0;
-
-    // The location data object contains the sharing interval (i), duration (d)
-    // and a location list (l). Each entry in the location list contains a
-    // latitude, longitude, timestamp, provider, accuracy and speed, in that
-    // order, as an array.
-    $session->addPoint([$lat, $lon, $time, $provider, $accuracy, $speed])->save();
-
-} else {
-    // Input validation cannot be performed for end-to-end encrypted data.
-    $lat = $_POST["lat"];
-    $lon = $_POST["lon"];
-    $time = $_POST["time"];
-    $speed = isset($_POST["spd"]) ? $_POST["spd"] : null;
-    $accuracy = isset($_POST["acc"]) ? $_POST["acc"] : null;
-    $provider = isset($_POST["prv"]) ? $_POST["prv"] : null;
-
+$lat = $_POST["lat"];
+$lon = $_POST["lon"];
+$time = $_POST["time"];
+$speed = isset($_POST["spd"]) ? $_POST["spd"] : null;
+$altitude = isset($_POST["alt"]) ? $_POST["alt"] : null;
+$accuracy = isset($_POST["acc"]) ? $_POST["acc"] : null;
+$provider = isset($_POST["prv"]) ? $_POST["prv"] : null;
+
+// The location data object contains the sharing interval (i), duration (d)
+// and a location list (l). Each entry in the location list contains a
+// latitude, longitude, timestamp, provider, accuracy and speed, in that
+// order, as an array.
+$point = [$lat, $lon, $time, $provider, $accuracy, $speed, $altitude];
+
+if ($session->isEncrypted()) {
     // End-to-end encrypted connections also have an IV field used to decrypt
     // the data fields.
     requirePOST("iv");
     $iv = $_POST["iv"];
 
     // The IV field is prepended to the array to send to the client.
-    $session->addPoint([$iv, $lat, $lon, $time, $provider, $accuracy, $speed])->save();
+    array_unshift($point , $iv);
+} else {
+    // Perform input validation
+    if (floatval($lat) < -90 || floatval($lat) > 90 || floatval($lon) < -180 || floatval($lon) > 180) die($LANG['location_invalid']."\n");
 }
 
+$session->addPoint($point)->save();
+
 if ($session->hasExpired()) {
     echo $LANG['session_expired']."\n";
 } else {
     echo "OK\n".getConfig("public_url")."?%s\n".implode(",", $session->getTargetIDs())."\n";
-}
+}
\ No newline at end of file
diff --git a/backend-php/dynamic.js.php b/backend-php/dynamic.js.php
index 325bead..47e2867 100644
--- a/backend-php/dynamic.js.php
+++ b/backend-php/dynamic.js.php
@@ -15,5 +15,8 @@
 var VELOCITY_DELTA_TIME = <?php echo json_encode(getConfig("v_data_points")); ?>;
 var TRAIL_COLOR = <?php echo json_encode(getConfig("trail_color")); ?>;
 var VELOCITY_UNIT = <?php echo json_encode(getConfig("velocity_unit")); ?>;
+var ALTITUDE_UNIT = <?php echo json_encode(getConfig("altitude_unit")); ?>;
+var SHOW_VELOCITY = <?php echo json_encode(getConfig("show_velocity")); ?>;
+var SHOW_ALTITUDE_AMSL = <?php echo json_encode(getConfig("show_altitude_amsl")); ?>;
 var OFFLINE_TIMEOUT = <?php echo json_encode(getConfig("offline_timeout")); ?>;
 var REQUEST_TIMEOUT = <?php echo json_encode(getConfig("request_timeout")); ?>;
diff --git a/backend-php/include/config-sample.php b/backend-php/include/config-sample.php
index 9b9d07d..9186369 100644
--- a/backend-php/include/config-sample.php
+++ b/backend-php/include/config-sample.php
@@ -274,6 +274,16 @@
 // KILOMETERS_PER_HOUR, MILES_PER_HOUR, METERS_PER_SECOND
 "velocity_unit"     => KILOMETERS_PER_HOUR,
 
+// The unit of measurement of altitude. Valid are:
+// METERS, FEET
+"altitude_unit"     => METERS,
+
+// Display velocity below marker
+"show_velocity"     => true,
+
+// Display altitude AMSL below marker
+"show_altitude_amsl"=> true,
+
 // The publicly accessible URL to reach Hauk, with trailing slash.
 "public_url"        => 'https://example.com/'
 
diff --git a/backend-php/include/inc.php b/backend-php/include/inc.php
index 64b6d16..318a455 100644
--- a/backend-php/include/inc.php
+++ b/backend-php/include/inc.php
@@ -59,6 +59,16 @@
     "mpsMultiplier" => 1,
     "unit" => "m/s"
 );
+const METERS = array(
+    // Absolute distance in meters
+    "metersMultiplier" => 1,
+    "unit" => "m"
+);
+const FEET = array(
+    // Absolute distance in feet
+    "metersMultiplier" => 3.280839895,
+    "unit" => "ft"
+);
 
 // Load fallback language.
 include(__DIR__."/lang/en/texts.php");
@@ -149,6 +159,9 @@
     "v_data_points"         => 2,
     "trail_color"           => '#d80037',
     "velocity_unit"         => KILOMETERS_PER_HOUR,
+    "altitude_unit"         => METERS,
+    "show_velocity"         => true,
+    "show_altitude_amsl"    => true,
     "public_url"            => 'https://example.com/'
 
 );
diff --git a/frontend/main.js b/frontend/main.js
index 14581d2..5bc0b3a 100644
--- a/frontend/main.js
+++ b/frontend/main.js
@@ -700,12 +700,13 @@ function processUpdate(data, init) {
         var lastPoint = shares[user].points.length > 0 ? shares[user].points[shares[user].points.length - 1] : null;
 
         for (var i = 0; i < users[user].length; i++) {
-            var lat = users[user][i][0];
-            var lon = users[user][i][1];
-            var time = users[user][i][2];
-            var prov = users[user][i][3];
-            var acc = users[user][i][4];
-            var spd = users[user][i][5];
+            var lat = getValueOrNull(users[user][i],0);
+            var lon = getValueOrNull(users[user][i],1);
+            var time = getValueOrNull(users[user][i],2);
+            var prov = getValueOrNull(users[user][i],3);
+            var acc = getValueOrNull(users[user][i],4);
+            var spd = getValueOrNull(users[user][i],5);
+            var alt = getValueOrNull(users[user][i],6);
 
             // Default to "Fine" provider for older clients.
             if (prov === null) prov = LOC_PROVIDER_FINE;
@@ -726,14 +727,23 @@ function processUpdate(data, init) {
                                 '<div class="arrow still-' + shares[user].state + '" id="arrow-' + shares[user].id + '"></div>' +
                                 '<p class="' + shares[user].state + '" id="label-' + shares[user].id + '">' +
                                     '<span id="nickname-' + shares[user].id + '"></span>' +
-                                    '<span class="velocity">' +
-                                        '<span id="velocity-' + shares[user].id + '">0.0</span> ' +
-                                        VELOCITY_UNIT.unit +
-                                    '</span><span class="offline" id="last-seen-' + shares[user].id + '">' +
+                                    '<span class="metric' + (SHOW_VELOCITY ? "" : " hidden") + '">' +
+                                        '<span class="metric-label">vel:</span>' +
+                                        '<span class="metric-value"><span id="velocity-' + shares[user].id + '">0.0</span> ' +
+                                        VELOCITY_UNIT.unit + '</span>' +
+                                        '<br>' + 
+                                    '</span>' + 
+                                    '<span id="altitude-container-' + shares[user].id + '" class="metric'+ (SHOW_ALTITUDE_AMSL ? "" : " hidden") + '">' +
+                                        '<span class="metric-label">alt:</span>' +
+                                        '<span class="metric-value"><span id="altitude-' + shares[user].id + '">0.0</span> ' +
+                                        ALTITUDE_UNIT.unit + '</span>' +
+                                    '</span>' + 
+                                    '<span class="offline" id="last-seen-' + shares[user].id + '">' +
                                     '</span>' +
                                 '</p>' +
                             '</div>',
-                        iconAnchor: [33, 18]
+                        // FIXME: hard-coded and dependend on style.css .marker
+                        iconAnchor: [48, 18]
                     });
                     shares[user].marker = L.marker([lat, lon], {icon: shares[user].icon}).on("click", function() {
                         follow(this.haukUser);
@@ -754,7 +764,7 @@ function processUpdate(data, init) {
                     shares[user].circle.setLatLng([lat, lon]);
                     if (acc !== null) shares[user].circle.setRadius(acc);
                 }
-                shares[user].points.push({lat: lat, lon: lon, line: line, time: time, spd: spd, acc: acc});
+                shares[user].points.push({lat: lat, lon: lon, line: line, time: time, spd: spd, acc: acc, alt: alt});
                 lastPoint = shares[user].points[shares[user].points.length - 1];
             }
         }
@@ -797,6 +807,20 @@ function processUpdate(data, init) {
             vel = velocity(dist, time);
             eVelocity.textContent = vel.toFixed(1);;
         }
+        
+        // Altitude (If available)
+        var eAltitude = document.getElementById("altitude-" + shares[user].id);
+        var alt = 0;
+        var eAltitudeContainer = document.getElementById("altitude-container-" + shares[user].id);
+        if (lastPoint !== null && lastPoint.alt !== null && eAltitude !== null) {
+            alt = lastPoint.alt * ALTITUDE_UNIT.metersMultiplier;
+            eAltitude.textContent = alt.toFixed(1);
+            if (SHOW_ALTITUDE_AMSL) {
+                eAltitudeContainer.classList.remove("hidden");
+            }
+        } else {
+            eAltitudeContainer.classList.add("hidden");
+        }
 
         // Flag that the first location has been received, for map centering.
         if (lastPoint !== null && !hasReceivedFirst) {
@@ -906,6 +930,14 @@ function processUpdate(data, init) {
     }
 }
 
+function getValueOrNull(points,idx) {
+    var value = null;
+    if (idx < points.length) {
+        value = points[idx];
+    }
+    return value;
+}
+
 // Calculates the distance between two points on a sphere using the Haversine
 // algorithm.
 function distance(from, to) {
diff --git a/frontend/style.css b/frontend/style.css
index 4967b12..4fb6db8 100644
--- a/frontend/style.css
+++ b/frontend/style.css
@@ -264,7 +264,7 @@ a:last-child > .store-icon {
 
 /* The outer marker div. */
 .marker {
-    width: 66px;
+    width: 96px;
     height: 62px;
 }
 
@@ -312,8 +312,8 @@ a:last-child > .store-icon {
     width: 100%;
     border-radius: 15px;
     text-align: center;
-    padding: 2px 0;
-    line-height: 100%;
+    padding: 5px 0 5px;
+    line-height: 125%;
     font-family: sans-serif;
     overflow: hidden;
     white-space: nowrap;
@@ -334,7 +334,7 @@ a:last-child > .store-icon {
     background-color: rgba(165,0,42,0.5);
 }
 
-.marker p.dead > span.velocity {
+.marker p.dead > span.metric {
     display: none;
 }
 
@@ -343,3 +343,20 @@ a:last-child > .store-icon {
     background: none;
     border: none;
 }
+
+.metric-label {
+    display:inline-block;
+    width: 30%;
+    text-align:right;
+    vertical-align: bottom;
+    padding-right: 0.5em;
+}
+  
+.metric-value {
+    display:inline-block;
+    width: 70%;
+    text-align: left;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    vertical-align: bottom;
+}