diff --git a/app/src/main/java/org/traccar/client/MainActivity.java b/app/src/main/java/org/traccar/client/MainActivity.java
index 03f39f3..e07f50c 100644
--- a/app/src/main/java/org/traccar/client/MainActivity.java
+++ b/app/src/main/java/org/traccar/client/MainActivity.java
@@ -24,6 +24,7 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
 import android.content.pm.PackageManager;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.preference.CheckBoxPreference;
@@ -35,7 +36,11 @@ import android.preference.TwoStatePreference;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
+import android.webkit.URLUtil;
+import android.widget.Toast;
 
+import java.net.MalformedURLException;
+import java.net.URL;
 import java.util.HashSet;
 import java.util.Random;
 import java.util.Set;
@@ -46,9 +51,7 @@ public class MainActivity extends PreferenceActivity implements OnSharedPreferen
     private static final String TAG = MainActivity.class.getSimpleName();
 
     public static final String KEY_DEVICE = "id";
-    public static final String KEY_ADDRESS = "address";
-    public static final String KEY_PORT = "port";
-    public static final String KEY_SECURE = "secure";
+    public static final String KEY_URL = "url";
     public static final String KEY_INTERVAL = "interval";
     public static final String KEY_DISTANCE = "distance";
     public static final String KEY_ANGLE = "angle";
@@ -65,12 +68,12 @@ public class MainActivity extends PreferenceActivity implements OnSharedPreferen
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-
         if (BuildConfig.HIDDEN_APP) {
             removeLauncherIcon();
         }
 
         sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
+        migratePreferencesIfNecessary(sharedPreferences);
         addPreferencesFromResource(R.xml.preferences);
         initPreferences();
 
@@ -80,30 +83,13 @@ public class MainActivity extends PreferenceActivity implements OnSharedPreferen
                 return newValue != null && !newValue.equals("");
             }
         });
-        findPreference(KEY_ADDRESS).setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+        findPreference(KEY_URL).setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
             @Override
             public boolean onPreferenceChange(Preference preference, Object newValue) {
-                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.FROYO) {
-                    return newValue != null && Patterns.DOMAIN_NAME.matcher((String) newValue).matches();
-                } else {
-                    return newValue != null && !((String) newValue).isEmpty();
-                }
-            }
-        });
-        findPreference(KEY_PORT).setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
-            @Override
-            public boolean onPreferenceChange(Preference preference, Object newValue) {
-                if (newValue != null) {
-                    try {
-                        int value = Integer.parseInt((String) newValue);
-                        return value > 0 && value <= 65536;
-                    } catch (NumberFormatException e) {
-                        Log.w(TAG, e);
-                    }
-                }
-                return false;
+                return (newValue != null) && setServerURL(newValue.toString());
             }
         });
+
         findPreference(KEY_INTERVAL).setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
             @Override
             public boolean onPreferenceChange(Preference preference, Object newValue) {
@@ -194,9 +180,7 @@ public class MainActivity extends PreferenceActivity implements OnSharedPreferen
 
     private void setPreferencesEnabled(boolean enabled) {
         findPreference(KEY_DEVICE).setEnabled(enabled);
-        findPreference(KEY_ADDRESS).setEnabled(enabled);
-        findPreference(KEY_PORT).setEnabled(enabled);
-        findPreference(KEY_SECURE).setEnabled(enabled);
+        findPreference(KEY_URL).setEnabled(enabled);
         findPreference(KEY_INTERVAL).setEnabled(enabled);
         findPreference(KEY_DISTANCE).setEnabled(enabled);
         findPreference(KEY_ANGLE).setEnabled(enabled);
@@ -307,4 +291,47 @@ public class MainActivity extends PreferenceActivity implements OnSharedPreferen
         }
     }
 
+    private boolean setServerURL(String userUrl) {
+        EditTextPreference preference = (EditTextPreference) findPreference(KEY_URL);
+
+        if (userUrl == null || userUrl.trim().length() == 0) {
+            preference.setText(getString(R.string.settings_url_default_value));
+            preference.setSummary(R.string.settings_url_summary);
+            findPreference(KEY_STATUS).setEnabled(true);
+            return false;
+        }
+        if (URLUtil.isValidUrl(userUrl) && (URLUtil.isHttpUrl(userUrl) || URLUtil.isHttpsUrl(userUrl))) {
+            preference.setSummary(R.string.settings_url_summary);
+            findPreference(KEY_STATUS).setEnabled(true);
+        } else {
+            preference.setSummary(R.string.settings_invalid_url_summary);
+            findPreference(KEY_STATUS).setEnabled(false);
+            Toast.makeText(MainActivity.this, R.string.msg_invalid_url, Toast.LENGTH_LONG).show();
+        }
+        return true;
+    }
+
+    private void migratePreferencesIfNecessary(SharedPreferences preferences) {
+        String port = preferences.getString("port", null);
+        if (port != null) {
+            Log.d(TAG, "migratePreferencesIfNecessary: migrating to URL preference");
+
+            String host = preferences.getString("address", getString(R.string.settings_url_default_value));
+            String scheme = preferences.getBoolean("secure", false) ? "https" : "http";
+
+            Uri.Builder builder = new Uri.Builder();
+            builder.scheme(scheme).encodedAuthority(host + ":" + port).build();
+            SharedPreferences.Editor editor = preferences.edit();
+            editor.putString(KEY_URL, builder.toString());
+
+            editor.remove("port");
+            editor.remove("address");
+            editor.remove("secure");
+            if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD) {
+                editor.commit();
+            } else {
+                editor.apply();
+            }
+        }
+    }
 }
diff --git a/app/src/main/java/org/traccar/client/Patterns.java b/app/src/main/java/org/traccar/client/Patterns.java
deleted file mode 100644
index 84f8857..0000000
--- a/app/src/main/java/org/traccar/client/Patterns.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton.tananaev@gmail.com)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.client;
-
-import java.util.regex.Pattern;
-
-public class Patterns {
-
-    private static final String IP_ADDRESS_STRING =
-            "((25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])\\.(25[0-5]|2[0-4]"
-                    + "[0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1]"
-                    + "[0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}"
-                    + "|[1-9][0-9]|[0-9]))";
-
-    private static final String UCS_CHAR = "[" +
-            "\u00A0-\uD7FF" +
-            "\uF900-\uFDCF" +
-            "\uFDF0-\uFFEF" +
-            "\uD800\uDC00-\uD83F\uDFFD" +
-            "\uD840\uDC00-\uD87F\uDFFD" +
-            "\uD880\uDC00-\uD8BF\uDFFD" +
-            "\uD8C0\uDC00-\uD8FF\uDFFD" +
-            "\uD900\uDC00-\uD93F\uDFFD" +
-            "\uD940\uDC00-\uD97F\uDFFD" +
-            "\uD980\uDC00-\uD9BF\uDFFD" +
-            "\uD9C0\uDC00-\uD9FF\uDFFD" +
-            "\uDA00\uDC00-\uDA3F\uDFFD" +
-            "\uDA40\uDC00-\uDA7F\uDFFD" +
-            "\uDA80\uDC00-\uDABF\uDFFD" +
-            "\uDAC0\uDC00-\uDAFF\uDFFD" +
-            "\uDB00\uDC00-\uDB3F\uDFFD" +
-            "\uDB44\uDC00-\uDB7F\uDFFD" +
-            "&&[^\u00A0[\u2000-\u200A]\u2028\u2029\u202F\u3000]]";
-
-    private static final String LABEL_CHAR = "a-zA-Z0-9" + UCS_CHAR;
-
-    private static final String IRI_LABEL =
-            "[" + LABEL_CHAR + "](?:[" + LABEL_CHAR + "\\-]{0,61}[" + LABEL_CHAR + "]){0,1}";
-
-    private static final String RELAXED_DOMAIN_NAME =
-            "(?:" + "(?:" + IRI_LABEL + "(?:\\.(?=\\S))" +"?)+" + "|" + IP_ADDRESS_STRING + ")";
-
-    public static final Pattern DOMAIN_NAME = Pattern.compile(RELAXED_DOMAIN_NAME);
-
-}
diff --git a/app/src/main/java/org/traccar/client/ProtocolFormatter.java b/app/src/main/java/org/traccar/client/ProtocolFormatter.java
index 17e47a1..aecf737 100644
--- a/app/src/main/java/org/traccar/client/ProtocolFormatter.java
+++ b/app/src/main/java/org/traccar/client/ProtocolFormatter.java
@@ -19,14 +19,12 @@ import android.net.Uri;
 
 public class ProtocolFormatter {
 
-    public static String formatRequest(String address, int port, boolean secure, Position position) {
-        return formatRequest(address, port, secure, position, null);
+    public static String formatRequest(String url, Position position) {
+        return formatRequest(url, position, null);
     }
 
-    public static String formatRequest(String address, int port, boolean secure, Position position, String alarm) {
-
-        Uri.Builder builder = new Uri.Builder();
-        builder.scheme(secure ? "https" : "http").encodedAuthority(address + ':' + port)
+    public static String formatRequest(String url, Position position, String alarm) {
+        Uri serverUrl = Uri.parse(url).buildUpon()
                 .appendQueryParameter("id", position.getDeviceId())
                 .appendQueryParameter("timestamp", String.valueOf(position.getTime().getTime() / 1000))
                 .appendQueryParameter("lat", String.valueOf(position.getLatitude()))
@@ -34,13 +32,19 @@ public class ProtocolFormatter {
                 .appendQueryParameter("speed", String.valueOf(position.getSpeed()))
                 .appendQueryParameter("bearing", String.valueOf(position.getCourse()))
                 .appendQueryParameter("altitude", String.valueOf(position.getAltitude()))
-                .appendQueryParameter("batt", String.valueOf(position.getBattery()));
+                .appendQueryParameter("batt", String.valueOf(position.getBattery()))
+                .build();
 
-        if (alarm != null) {
-            builder.appendQueryParameter("alarm", alarm);
+        if (alarm != null && alarm.trim().length() != 0) {
+            serverUrl = serverUrl.buildUpon().appendQueryParameter("alarm", alarm).build();
         }
-
-        return builder.build().toString();
+        int port = serverUrl.getPort();
+        if (port < 0 || port > 65535) {
+            port = 5055;
+            String host = serverUrl.getHost();
+            serverUrl = serverUrl.buildUpon().encodedAuthority(host + ":" + port).build();
+        }
+        return serverUrl.toString();
     }
 
 }
diff --git a/app/src/main/java/org/traccar/client/ShortcutActivity.java b/app/src/main/java/org/traccar/client/ShortcutActivity.java
index 27fcb68..ac3ddd8 100644
--- a/app/src/main/java/org/traccar/client/ShortcutActivity.java
+++ b/app/src/main/java/org/traccar/client/ShortcutActivity.java
@@ -64,10 +64,7 @@ public class ShortcutActivity extends Activity {
                     location, PositionProvider.getBatteryLevel(this));
 
             String request = ProtocolFormatter.formatRequest(
-                    preferences.getString(MainActivity.KEY_ADDRESS, null),
-                    Integer.parseInt(preferences.getString(MainActivity.KEY_PORT, null)),
-                    preferences.getBoolean(MainActivity.KEY_SECURE, false),
-                    position, ALARM_SOS);
+                    preferences.getString(MainActivity.KEY_URL, null), position, ALARM_SOS);
 
             RequestManager.sendRequestAsync(request, new RequestManager.RequestHandler() {
                 @Override
diff --git a/app/src/main/java/org/traccar/client/TrackingController.java b/app/src/main/java/org/traccar/client/TrackingController.java
index 6e42ef8..9ffbf3d 100644
--- a/app/src/main/java/org/traccar/client/TrackingController.java
+++ b/app/src/main/java/org/traccar/client/TrackingController.java
@@ -36,9 +36,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     private Handler handler;
     private SharedPreferences preferences;
 
-    private String address;
-    private int port;
-    private boolean secure;
+    private String url;
 
     private PositionProvider positionProvider;
     private DatabaseHelper databaseHelper;
@@ -73,9 +71,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
         networkManager = new NetworkManager(context, this);
         isOnline = networkManager.isOnline();
 
-        address = preferences.getString(MainActivity.KEY_ADDRESS, null);
-        port = Integer.parseInt(preferences.getString(MainActivity.KEY_PORT, null));
-        secure = preferences.getBoolean(MainActivity.KEY_SECURE, false);
+        url = preferences.getString(MainActivity.KEY_URL, null);
 
         PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
         wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, getClass().getName());
@@ -199,7 +195,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     private void send(final Position position) {
         log("send", position);
         lock();
-        String request = ProtocolFormatter.formatRequest(address, port, secure, position);
+        String request = ProtocolFormatter.formatRequest(url, position);
         RequestManager.sendRequestAsync(request, new RequestManager.RequestHandler() {
             @Override
             public void onComplete(boolean success) {
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 790d8c0..f317354 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -6,10 +6,9 @@
   <string name="shortcut_stop">Traccar - Stop</string>
   <string name="shortcut_sos">Traccar - SOS</string>
   <string name="settings_id_title">Device identifier</string>
-  <string name="settings_address_title">Server address</string>
-  <string name="settings_address_summary">Domain name or IP address</string>
-  <string name="settings_port_title">Server port</string>
-  <string name="settings_port_summary">Tracking server TCP port</string>
+  <string name="settings_url_title">Server URL</string>
+  <string name="settings_url_summary">Tracking server URL</string>
+  <string name="settings_url_default_value" translatable="false">http://demo.traccar.org</string>
   <string name="settings_interval_title">Frequency</string>
   <string name="settings_interval_summary">Reporting interval in seconds</string>
   <string name="settings_distance_title">Distance</string>
@@ -21,11 +20,6 @@
   <string name="settings_status_on">Stop</string>
   <string name="settings_status_off_summary">Service stopped</string>
   <string name="settings_status_on_summary">Service running</string>
-  <string name="settings_secure_title">Encryption</string>
-  <string name="settings_secure_off">Enable</string>
-  <string name="settings_secure_on">Disable</string>
-  <string name="settings_secure_off_summary">Encryption disabled</string>
-  <string name="settings_secure_on_summary">Encryption enabled</string>
   <string name="settings_provider_title">Location provider</string>
   <string name="settings_provider_summary">Source of location data</string>
   <string name="settings_provider_gps">GPS provider</string>
@@ -33,9 +27,7 @@
   <string name="settings_provider_mixed">Mixed provider</string>
   <string name="settings_foreground_title">Foreground service</string>
   <string name="settings_foreground_summary">Increase service priority</string>
-  <string name="error_invalid_address">Invalid server address</string>
-  <string name="error_invalid_port">Invalid server port</string>
-  <string name="error_invalid_frequency">Invalid frequency value</string>
+  <string name="settings_invalid_url_summary">Invalid server URL</string>
   <string name="menu_status">Status</string>
   <string name="menu_about">About</string>
   <string name="menu_shortcuts">Add shortcuts</string>
@@ -51,4 +43,5 @@
   <string name="status_connectivity_change">Connectivity change</string>
   <string name="hidden_app_name">Device Settings</string>
   <string name="hidden_alert">The app has been hidden. To open it again please dial 8722227 (TRACCAR).</string>
+  <string name="msg_invalid_url">Please enter a valid http:// or https:// URL</string>
 </resources>
diff --git a/app/src/main/res/xml-v14/preferences.xml b/app/src/main/res/xml-v14/preferences.xml
index a402b81..941eae5 100644
--- a/app/src/main/res/xml-v14/preferences.xml
+++ b/app/src/main/res/xml-v14/preferences.xml
@@ -15,26 +15,10 @@
         android:title="@string/settings_id_title" />
 
     <EditTextPreference
-        android:defaultValue="demo.traccar.org"
-        android:key="address"
-        android:summary="@string/settings_address_summary"
-        android:title="@string/settings_address_title" />
-
-    <EditTextPreference
-        android:defaultValue="5055"
-        android:key="port"
-        android:numeric="integer"
-        android:summary="@string/settings_port_summary"
-        android:title="@string/settings_port_title" />
-
-    <SwitchPreference
-        android:defaultValue="false"
-        android:key="secure"
-        android:summaryOff="@string/settings_secure_off_summary"
-        android:summaryOn="@string/settings_secure_on_summary"
-        android:switchTextOff="@string/settings_secure_off"
-        android:switchTextOn="@string/settings_secure_on"
-        android:title="@string/settings_secure_title" />
+        android:defaultValue="@string/settings_url_default_value"
+        android:key="url"
+        android:summary="@string/settings_url_summary"
+        android:title="@string/settings_url_title" />
 
     <EditTextPreference
         android:defaultValue="300"
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index c704c10..4a0f590 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -13,24 +13,10 @@
         android:title="@string/settings_id_title" />
 
     <EditTextPreference
-        android:defaultValue="demo.traccar.org"
-        android:key="address"
-        android:summary="@string/settings_address_summary"
-        android:title="@string/settings_address_title" />
-
-    <EditTextPreference
-        android:defaultValue="5055"
-        android:key="port"
-        android:numeric="integer"
-        android:summary="@string/settings_port_summary"
-        android:title="@string/settings_port_title" />
-
-    <CheckBoxPreference
-        android:defaultValue="false"
-        android:key="secure"
-        android:summaryOff="@string/settings_secure_off_summary"
-        android:summaryOn="@string/settings_secure_on_summary"
-        android:title="@string/settings_secure_title" />
+        android:defaultValue="@string/settings_url_default_value"
+        android:key="url"
+        android:summary="@string/settings_url_summary"
+        android:title="@string/settings_url_title" />
 
     <EditTextPreference
         android:defaultValue="300"
diff --git a/app/src/test/java/org/traccar/client/ProtocolFormatterTest.java b/app/src/test/java/org/traccar/client/ProtocolFormatterTest.java
index 2e6f371..cc6064c 100644
--- a/app/src/test/java/org/traccar/client/ProtocolFormatterTest.java
+++ b/app/src/test/java/org/traccar/client/ProtocolFormatterTest.java
@@ -22,10 +22,17 @@ public class ProtocolFormatterTest {
         Position position = new Position("123456789012345", new Location("gps"), 0);
         position.setTime(new Date(0));
 
-        String url = ProtocolFormatter.formatRequest("localhost", 5055, false, position);
-
-        assertEquals("http://localhost:5055?id=123456789012345&timestamp=0&lat=0.0&lon=0.0&speed=0.0&bearing=0.0&altitude=0.0&batt=0.0", url);
-
+        String url = ProtocolFormatter.formatRequest("http://localhost:5055/path", position);
+        assertEquals("http://localhost:5055/path?id=123456789012345&timestamp=0&lat=0.0&lon=0.0&speed=0.0&bearing=0.0&altitude=0.0&batt=0.0", url);
     }
 
+    @Test
+    public void testFormatAlarmRequest() throws Exception {
+
+        Position position = new Position("123456789012345", new Location("gps"), 0);
+        position.setTime(new Date(0));
+
+        String url = ProtocolFormatter.formatRequest("http://localhost:5055/path", position, "alert message");
+        assertEquals("http://localhost:5055/path?id=123456789012345&timestamp=0&lat=0.0&lon=0.0&speed=0.0&bearing=0.0&altitude=0.0&batt=0.0&alarm=alert%20message", url);
+    }
 }